Worth every penny if you require quality and value.
Positive Product Points
Spectacular value for the money, the Tea produces very consistent results, and is very reliable when cared for properly. Maintenance is straightforward when needed, and modification is similarly straightforward. Steaming power is awesome, and the extra gauges satisfy the information geek who wants to know all the details of what is going on. Also, from a purely subjective point of view, this is the best looking machine out there.
Negative Product Points
Water resevoir is too small for frequent use, easily rusting screws are used in the drain/drip tray, and the default steaming tip is harder to use on small volumes of milk. The gasket is quite difficult to remove when cleaning the E61 head. These can all be worked around for the most part.
Perhaps a key reason I purchased the machine was because I had used many non-heat exchange machines and lacked the patience to continue to deal with them on a daily basis.
The Tea offers another wonderful bonus I desired, the ability to brew on demand, non-stop, any kind of specialty drink I can imagine from a cafe for my guests. That is so wonderful, I cannot begin to describe it's value, even on the casual basis for which I generally gather people in my home.
There are many machines in the same league now (at this price/value level), but the only machines that have tempted me were all significantly more expensive.
First the 'bad', or at least issues you may end up dealing with to make your experience with the Tea even more pleasant. I've dealt with these issues for nearly a year now, waiting to see what is irritating and what really isn't. The quick version is, all the issues can be addressed without getting a different machine.
The water resevoir is quite small. I was able to use it for many months without any real problems except the hassle of always filling it before or after each use of the machine (to keep the auto shutoff feature from becoming a hassle). The first time that auto shutoff feature kicks in, you will be convinced your machine is broken. Afterwards, it becomes the first thing you check. I finally solved this minor annoyance by installing a float system and now only check the resevoir once a month for cleaning.
I received a different steaming tip from the retailer free of charge, and that made it simpler to steam smaller volumes. I still switch to the old tip when steaming larger volumes, as that tip works great for that.
The last 'bad' issue I mention merely because I've seen it in other reviews and want to add my perspective. When the machine has been sitting for a while, water in the exchanger will overheat to the temprature of the steam boiler, which is too hot for ideal espresso extraction. That's just plain physics, and the 'fix' is quite simple... pull 6-8oz of water from the machine (I preheat my mugs with this water while grinding my beans) before pulling a shot. When pulling many shots in a row, this is a non-issue after the first shot and the temperature is very stable.
This is seen as a negative by many, but the only alternative is to own a machine that cannot steam at the same time (I steam while pulling shots all the time), or spending 2-3 times as much for a dual boiler system. It is simply an artifact of the engineering design and EVERY heat exchange machine has this and quite honestly, even some of the non-heat exchange machines have this a little bit.
Maintenance will be an issue with any long term device that you use, especially one that regularly maintains steam pressure, and heats up and cools down. I've had to perform minor maintenance on this machine a few times, and the hardest thing I've had to do was remove the gasket in the E61 brewing head (for cleaning). It's a pain in the butt and while experience is a great teacher, it's probably the only weakness in the design I wish was improved upon. You shouldn't even attempt it until you have a replacement gasket on hand, because without experience, you will trash it.
Getting into the back of the machine is simple and repairing/replacing things like aged gaskets is very easy. I consider it a benefit that these particular machines have manual rather than automatic dispensing systems, as there are no chips to change, or computer components to fail. I've even been able to jury rig gasket repairs with hardware store replacements until I could be mailed the correct part.
To talk about the more positive aspects of my experience with the machine, I've hard little difficulty in using it and have been able to produce superior espresso with it. I also home roast, which ads to the advantage, but a friend who loves and travels a lot in Italy has always enjoyed my results. The machine is quite stable thermically when used properly, and I have converted many family and friends to roasting or otherwise changing their coffee/tea habits.
The gauges are very useful to measure when things are going well (or poorly). For example, a poorly packed bed of coffee will let a flow start before the pressure builds up to 9-10 bars and where the pressure is at can also be an indicator of my grind or pack both. There are some people who vary their grind/tamp by the response on the pressure gauge rather than other more common factors.
I also use the gauges when backflushing (pressure needs to max out for a few seconds before I turn off the pump).
The drip tray is enormous and I only wish I was in a situation where I could somehow plumb it in as well.
The look of the machine is very clean, but every drip and water spot does show, so you need to wipe it down with a microfiber towel from time to time.
There are other great uses for almost any espresso machine you keep in your kitchen that can be left on all the time. Making tea or any hot drink in our household has been adapted to use the machine. Making simple soups such as miso is just as easy. Strangely, I've also found it useful for steaming eggs (they get nicely scrambled by the effect).
My buying experience has been exemplary, as pretty much anyone who uses Chris' Coffee Service has expressed. I received a Mazzer Mini for cost as part of the purchase and I have always received excellent (frankly, spectacular) follow up service from Chris personally when required. It was when having my first conversation with Chris that I changed my coffee experience back to beginner, and there it is likely to stay forever.