If you find one for around $20 - go for it. But remember the boiler warning.
Positive Product Points
Easy to use and I have two. One was a gift and the other I bought for fifteen dollars for spares. Because you can only brew one decent coffee at a time, and the second one is never as good as the first, I now have both machines set up and can easily make two pretty well identical coffees. I am not a barista and I am not a coffee expert. I do have a few different coffee appliances including pump and boiler electrics, and a Bellman stove top. I also compare what I manage to produce with supposedly decent coffee houses. Visitors who ARE coffee geeks often ask for my coffee rather than go to a coffee shop.
Negative Product Points
All plastic, and I worry a little about the, apparently plastic, boiler. The only way to make really nice coffee is to forget the instructions and make it 'properly' as suggested below.
Ok, it took forever to understand the little Krups. First, if you throw away the instructions as I did, you might be risking a boiler explosion. Keep your head away from the thing. Buy a burr grinder and grind decent beans fairly fine, like you would for a pump type home machine.
Fill the basket to the brim loosely, then TAMP. I actually LEAN on the tamper. I made one from a plastic end of a tamping spoon, but later I bought a cheap alloy one. SPIN the tamper to polish the top of the coffee. That is particularly important in this little machine, to prevent water channeling when pressure builds up. The big complaint about this machine is that there is no crema and that it scalds or burns the coffee. You can stop this. Get a shot glass and a timer. If you tamp sensibly you will find the shot glass fills time after time in 25 seconds and there might be about 1/8 to 1/4 inch of red/gold/brown fine foam across the top. A lot depends on how good and fresh your beans are!
Get used to how the stream coming out of the holder looks and when it starts to blow bubbles and turn 'watery'. You can actually hear this happen as steam instead of hot water begins to get into your coffee and ruin it.
Fill the tank until the water is just below the ridge you can see sticking out around the grey pipe. About an inch below the neck of the boiler, maybe a little more but not too much. Screw the lid on properly. Close the steam knob. One of my bravos has a thick alloy holder and the other is plastic.
Put the basket in the holder and attach to the machine. Turn on the power and place a cup under the holder. While it is heating put some cold milk in whatever you use to foam the milk. I use a stainless steel camping mug that I bent a spout into. The milk pitchers are usually too deep for the steam pipe, and take too long to heat.
When you see the first trickle of brown stuff, start the timer or check a clock. watch the stream very carefully. I quickly empty this first bit, it is bitter. But only enough to cover a 10 cent coin in the bottom of the cup, so don't worry about it too much. Around 20-25 seconds later you will see a couple of long bubbles start in the stream. About now is the time to take out your coffee cup and replace it with something else. If you let many more bubbles start, you WILL start to get burnt coffee and you can actually smell it burning.
Set the coffee cup down. Depending on the grind and tamping you should have between 1/8 and 1/4 inch of red golden and dark mixed fine bubbles across the surface. What colour I get depends on the coffee.
Forget the frothing attachment. Open and close the steam knob to clear any water. Put the nozzle just under the surface and mess with the angle of the pitcher until you have the milk swirling in a circle. Use a milk thermometer and shut off just before the needle hits the red. If you open the steam knob about 1/4 turn +/- you can get a nice swirl going in the milk. It takes 20 seconds to foam and you can make such tiny bubbles you can barely see them, but the milk is creamy after you heat it. Turn off the steam, swirl the milk a little and tap it firmly on the counter top to settle it. Any larger bubbles will pop.
You can learn to foam any milk. I like UHT full cream milk because I like the sweetness. I also use ordinary full cream milk. I can foam skim, semi skim and believe it or not, full cream and skim powdered milk! So there is no excuse not to have a nice drink.
Put the milk down and turn the steam knob on and off, wipe it clean and turn the knob back on the release pressure. Wipe the thermometer.
The ten seconds or so that took will settle the milk nicely. Done right you will still have about 1/8 inch, maybe only 1/16 inch of lovely gold foam over the top of your coffee. Maybe not as nice as real espresso, but it tastes fine (try it). If you can swirl it around your mouth and taste the flavour without wanting to spit it out, you will see why I love this little machine.
Tilt the coffee cup slightly and pour the milk down the side so it runs under the foam and as the level rises the foam will blend into the foam on top of the milk. Now you have a pretty golden cap across the top of your milk that will be around an inch deep but no visible 'bubbles' adn a sort of light tan/gold all the way through.
You can play with this stuff. I like to dig it out with a spoon, turn it upside down and wonder how something apparently devoid of bubbles can just hang there.
Maybe it is not a real espresso, and perhaps it is not a real cappuccino. The fact is though that is tastes good enough to fool most people and can taste better than a bought one at a cafe like Starbucks of Coffee Club.
These machines are pretty old now but they crop up on ebay and garage sales from time to time. I didn;t like coffee much until I learned what you can do with this thing. Now I drink the black smooth coffee with the reddish gold foam 'raw' from my little Krups.
Since I wrote this I've added several other coffee machines to my collection, one costing around $1000. The little Krups is still the only one that consistently makes an espresso type (short black) that tastes sweetish and syrupy even with a double dose of coffee.
It is the only one of my machines that makes capps and lattes that people like to drink with no sugar, but still enjoy a stronger than normal coffee flavour.
One was a gift, the other was in a second hand shop.
Three Month Followup
I have modified the tips in the original post mainly because I got a better grinder and now know what 'fine' is. However, the rest is the same. My most expensive coffee machine is now sitting behind the Krups and is used to make chocolate drinks, scrambled egg and tea. The Krups is used for coffee, and when I have visitors it is not unusual to see both Krups 871 machines pressed into service to speed things up. This is actually written long after the 3 months :-)
One Year Followup
I now have several coffee makers and the Krups 871 is still my favourite for consistent smooth tasty coffee with or without milk, and I never need sugar. With my other machines and the same store bought beans, it is not as nice without sugar. I use the Krups 871 to make the espresso and at the same time I foam the milk on the Breville 800.
One thing with the 871 - ALWAYS let the steam pressure drop completely BEFORE you remove the portafilter. I've lost count of the times I had to clean coffee grounds off various parts of the walls, bench, appliances, floor - you get the idea?