The Baby... what an icon Gaggia has produced and maintained over the years. Its name implies mediocrity, even perhaps under-development. Although, as many have already noted, the Baby is a great espresso machine and a great stepping stone towards making exceptional espresso.
There are many great positive things about the Baby, but I will be brief about these items, since I feel that it is the negatives which should be well-noted. In general, my impression is that every product initially has a blank slate of being perfect. Identifying and elaborating over its inadequacies is critical towards deciding whether it is a good buy or not. Please remember to read other Baby reviews and use my opinions only as one piece of the decision-making puzzle!
The Baby makes great espresso. For the most part, I drink espresso straight: singles, doubles, ristrettos. With fresh beans, a consistent grind and tamp, the Baby makes superb espresso. Crema-laden, reddish-brownish, bittersweet nectar, etc. Its boiler and pump are capable of making good espresso when surrounded by quality goods and equipment. I use home-roasted beans (Sweet Marias) and fresh beans (Cafe Moto) with a Rocky grinder and an Ergo Tamper. Let the Baby warm up ~15 minutes and pour a blank shot, and everything is well. Also, it came with a crema-disc, do not use it.
Now, on to the detailed negatives of the Baby. Keep in mind, the following paragraphs are meant to be critical in painful detail. First item is the steaming function of the Baby (which I personally rarely use). The wand is fixed in position, so getting items under and around, etc. is more difficult compared to adjustable wands found on most machines today. The steaming power is adequate, however the control over steaming is terrible! The Baby's steam is dispensed by pressing a push-button. So, the steam is either on or off. There is no adjustablity in the volume of steam. I find this very inconvenient and would refer to it as a design flaw. If you are serious about steaming and having control over the function, make sure you find a knob-adjusting machine. The push-button function of dispensing water to the grouphead and water through the steam wand is perfectly fine.
The drip tray is a spot for another concern. Yes, it is a drip tray and it is where things are to drip into, however, it quickly becomes a fountain tray. The 3-way solenoid valve automatically redirects water to the drip plate after pulling a shot. In addition, water from the grouphead drips into the plate. My personal use of the Baby coupled with the small volume of the receptacle requires emptying the drip tray once every 3 uses (which means I empty it ~once per day). I realize there is little to reconcile the issue due to the fact that the Baby is not a commercial machine. However, I feel a larger volume drip tray would make the Baby slightly more functional. Furthermore, the removal of the drip tray (to empty it) is difficult, as it is placed in a recess in the base of the machine and has no good grips. In addition, the solenoid valve tube has to be moved out of the way in order to remove the tray, often causing a large mess and pools of espresso water.
Lastly, although the portafilter is commercial-sized (58 mm, which carries its perks), it lacks in quality. This negative commentary is largely based on aesthetics, although one may argue function as well. The square-shaped (vs. rounded) handle makes it uncomfortable to use (this has been harped-on by previous reviewers). Also, the spouts are built into the portafilter. They are small and lack proper "pouring" of espresso. This results in espresso pouring out irregular when compared to traditional commercial spouts. This may or may not affect the quailty of espresso, as I have tasted top notch espresso from $100 pump machines with hideously looking and shaped portafilters. If you are just starting to make espresso at home, I'd like to take this opportunity to re-iterate the importance of fresh beans, a good grinder and a fitted tamper.
Please take into consideration my above commentary about my personal beliefs (that to me, the negatives are a little more pertinent than the positives). Don't mistake my opinion of the Baby: It is a quality machine that makes excellent espresso! I would highly recommend this, in addition to Gaggia's other upper-tier home machines.
ps-The Baby has an aluminum boiler (as with all the other Gaggia home machines, I think), so make sure you use a cleaner such as CleanCaf on a regular basis, especially if you're using tap water. Al readily oxidizes and form particulates. Subjecting the boiler to a cleaner will prevent build-up of particulates in your machine and will keep valves clean (prevents leak) and make your espresso more palatable.
Also, to make sure you are aware of all of the Baby's perks, go to an online dealer and read about its features (Whole Latte Love, etc.).