I use a 1/4", 3/8" daily..... I think they are great ratchets; that being said, I have a couple of things I don't like! These seem to be the criticisms I hear around here and some of my own sense of things that could be improved about the design.
1. the edges of the ratchet, are very square and sharp... most likely because of the CAD/CNC design and production process. I would prefer a little more "organic" feel to them and not so dramatically square edges; if you look at previous designs , they seem more human friendly and not so starkly geometric. When handling the head of these ratchets; I can feel a very square edge in my hand. The shapes from the 50's really were beautiful with a human and organic flow to them! They seem to have lost some of the "soul" of the earlier ratchets.... heck, they were designed on drafting table by hand, hand crafted; not by CAD or CNC!
2. The lever.... I think it is too small, wimpy, doesn't stick out enough to be as easily switched as it should be; I prefer the 900 series lever, as a example.
3. There have been complaints about the size of the head; this seems to be a outgrowth of the 80/72 tooth gear design (bigger head, to enclose a bigger gear).... the 800 series heads are quite a bit smaller in comparison.
4. ratchet mechanism failure; some on this board have complained about continual failure of the ratchet mechanism, some saying they prefer the 900 (36 tooth) ratchet in this regard. The failures, seem to be mentioned in the 1/2", 3/8" size in heavy duty applications; such as heavy line work. I haven't had any fail but I don't work on heavy equipment.... I'm also not as strong as many of these guys around here! I tend to up a drive size and handle length on my ratchets; depending on the applications, and I have enough ratchets to fit most, if not all situations I run into. All ratchets have a failure point; if the tool can't do what you want it to do... you probably need a different tool or approach what your doing in a different way!
5. Some feel the chrome is not as good; well, its because they are using a different chrome process and from what I can tell, it cannot be the same as previous processes. The new trivalent and nickle chrome plating; just can't seem to replicate the old hexavalent process fully. The change to trivalent; is a combination of; EPA, cost, and production issues... that are a demand here in the first world, while countries like China don't need to concern themselves with! More info about the processes, here:
http://www.garagejournal.com/forum/showthread.php?t=78698&highlight=ratchet&showall=1
Most of what I am saying is probably nitpicking and in the realm of "tool art criticism"; many here will probably say... "its just a tool, use it!"; but.... if we weren't tool aficionados (tool freaks) we wouldn't have joined this site and spend money, time. effort etc. on tools such as Snap-On, would we?

Bottom line; I like them and want to get more!

But I also appreciate the earlier designs; for their shape, design, feel and chrome quality!