I wanted an inexpensive HX machine for work, something that would work well but also something that I would not feel despondent should it go walking. The Gaggia Baby I was using was definitely inexpensive and low-profile, but it was limited in performance. The BZ02S fits the bill well.
I like the design. I appreciate stainless steel and chrome, but it gets to be overkill after a while. I really like the way Bezzera used both steel and plastic on this machine. I would be happy to keep it at home, too. It is a very contemporary design that also seems somewhat classic, if such a thing exists. The BZ02 is slightly wider than a typical machine of its ilk, but its dimensions are reasonable. Mine sits on a table in the back of a room and is relatively inconspicuous. It managed to go unnoticed for several weeks before someone noticed I had a different espresso machine, a good thing in my instance. The adjustable feet are big and easy to use, and the case is fairly easy to clean. On top of the machine, cups rest on a removable grate that is maybe 1cm high, so while it is easy to take off, the height reduces heat transferred from the boiler to cups. I like the curved front, but the middle is very close to the boiler and gets hot, natch.
The drip tray is very large but shallow. It holds a fair amount of water, probably more than one might think. The tray cover is nicely heavy steel and comes out easily. The plastic tray itself, though, is a tight fit in the back and will spill when attempting to remove it with anything inside. My fix is to not remove it when anything is inside. I believe a CG'er attached a drain to the bottom, something which would be easy to do.
The internals of the BZ02S are essentially the same as the Pasquini Livia. That is because Bezzera builds the Livia for Pasquini. Parts are available, no problem. The frame is nicely solid, though the case is slightly doinky. Several different pieces bolt together, and the side panels have somewhat cheap nibs which press into spring-loaded points in the frame. It all connects solidly, but is a bit silly the way it works, reminiscent of an Erector set. There is quite a bit of give-and-take in the way the pieces bolt together, so if a machine seems to have poor fit, it is possible to loosen some screws and make it fit better with some tweaking. The boiler is vertical and its pressure-bleed valve is on its top, directly below the cup warmer tray. Some moisture thus gets blown to the inside of the case top. I do not think there is a significant risk of rust or water getting into electronics, but a more elegant design whereby the valve drains away from the boiler would have been nice
The group uses a combination of thermoblock and HX designs. It is directly attached to the boiler though a large brass piece and water is siphoned through internal and external passageways. Unlike most HX machines, the BZ02 does not need a cooling flush. I have tried several different techniques and have found that, after a 20-30 minute warm-up, a single shot (only an ounce or two) is all that should be drawn before use. I leave the portafilter in during warmup so that it does not need water run through it to get hot. I have read about the Livia being sensitive to dose amount: From my experience, most machines are anyway. I have been dosing approximately 14g and have had no issues. I stopped weighing and now dose visually with perfectly consistent results. In short, I have experienced no unusual dosing issues. In fact, the BZ02 is the most forgiving machine I have used, but my other espresso machine is a lever.
The BZ02 is truly simple to use. Warm up, quick shot to clean the dispersion screen, and go. Hot water and steam are very good. I have not yet had occasion to try steaming while drawing shots. I love the one-gallon reservoir. Lift the cover and pour water in. Easy. I do not have ready access to water where the machine is located, so the machine's simple operation and big reservoir are very nice. Although the reservoir has a cover, it is effectively open to the air, so I am sure some water is lost to evaporation that machines with screw-top reservoirs maintain. In the real world, evaporation is not an issue. Easy access to the reservoir (Did I mention how easy it is to remove? Just lift it out.) trumps that concern in my view.
I really cannot think of significant caveats with the BZ02. It performs as well as some machines that cost several hundred dollars more. If you want an E61 group, then this is not what you want. Consider whether or not you really need an E61-style group. This machine produces great shots and is super easy to operate, so maybe all the E61 fuss is something for a hobby. It was a big paradigm shift for me to stop looking for something like an Expobar or Quickmill, but I am glad I got over that E61 HX-itis.