Excellent espresso from a solid, if quirky, low-end machine.
Positive Product Points
Easy to use, makes great espresso every time! The pump and water heater system work quickly, I can make several shots back to back and the machine seems happy to keep up with me.
Negative Product Points
Price for new machines is too high, maybe some quality issues (based on reviews I've seen elsewhere), comes with pressurized filter baskets. Programmable feature is probably helpful, but I find the water volume to be inconsistent. The drip tray is a bit small, so make sure you empty it often!
Detailed Commentary
I bought this machine refurbished at Burlington Coat Factory. They now have refurb xp 4030s for $20, and I'm going to pick one of those up just for the spare parts. I have been tinkering with espresso machines for the past 8 years or so, and have been drinking the terrible stuff since I was a little kid living in Europe. So I know what I like. Cheap, smooth espresso from a medium-light roasted arabica.
The Krups xp4050 allows me to pull smooth shots with no mess, no confusion, and no real work. Programming the single and double shots was fairly simple, but the water volume is not very consistent, so I don't count on the machine to decide how much espresso I'll have in any given shot - I just flip it off when I'm satisfied. The main problem I faced until recently was getting the grind fine enough to pull a real shot. Until I bought my Capresso Infinity, I was using a machine (La Pavoni/Alpina cg600) that required several (started at 2, now up to 4) passes for optimum grind. The Capresso Infinity does the job for me, and I won't be buying a new grinder until I can afford a real espresso machine (which at this point seems unnecessary, given the results I can get from my $50 Krups!).
The tamper that comes with the machine is a bit too small, and very light, so I ended up making my own. Filter basket is 52.5mm outside diameter and 51.5mm inside, so I'd recommend buying a non-pressurized version if you can track one down (Amazon has them in July 2010). The drip tray has a handy little float mechanism that should warn you when it's filling up (a blue tab floats to the surface and pops up under the drip tray grid when it's full), so pay close attention to that to avoid making a mess on the counter. For less than $50, there is no comparable machine anywhere, but I'm not sure I'd be as happy with it had I paid the $200 that some companies are asking for the new ones.
I'd guess that all the negative reviews I see on Amazon are from people who either don't quite have the experience to work out some of the kinks in the machine early on, or that Krups has relatively low quality control at the factory, meaning a lot of people end up with lemons (that might explain why I could find a refurb machine at such a low price). Either way, I'm pretty sure anyone with a bit of patience can pull some mean shots out of the xp4050, especially once you've got the grind and tamp system worked out (and that goes for any pump machine, I suppose). I'm very satisfied with my purchase!
Buying Experience
Refurbished machine from Burlington Coat Factory, I'm so happy with this one that I bought an xp 2070 (basically the same machine, with a coffee maker built in), and I'm looking at buying an xp 4030 for the replacement parts. For the price, I really don't think there's a comparable machine out there.