Alright, here goes.
I'm probably going to come off as a Boba Fett elitist. I'm writing this from the perspective of 'how does it compare to the screen-used suit,' so please keep that in mind.
The overall figure is great. As with the 1/4 scale figure, the attention to detail is astonishing. This is a more complete Boba Fett than has ever been offered in this scale, and the VAST majority of the details are totally intact, along with several details that didn't really need to be included in order for this figure to be super sweet. The most apparent example of this is, like the 1/4 scale figure, the jetpack harness (the third little 'belt'). If Hot Toys chose not to include this, very few people would notice, and even fewer would actually complain.
Hot Toys put forth a completely awesome effort regarding paint. The details are MOSTLY correct for the Return of the Jedi suit, and the figure's paint work is, in true Hot Toys tradition, quite intricate. Multiple colors were used, even for the similar greens that appear on the armor/helmet.
The underlying body is awesome, and provides amazing articulation, MUCH more so than the 1/4 scale figure. Deep poses are still a little out of reach, but that's because the suit is slightly restrictive, and, really, how many deep poses does Boba Fett need to achieve? The neck is a bit short, so this makes the figure look a little squat.
The sculpting of the pieces of the figure are where things go a little off-track. Like the 1/4 scale figure, the helmet shape is poor, perhaps even more so here. This is the most frustrating part for me, since Boba Fett IS his helmet. In a general sense, it's totally fine, but once you pass into the more in-depth areas of the Fett helmet, the inaccuracies really jump out. The shape is extremely flat in the back, the visor is wrong in every imaginable way, and the rangefinder is incorrect. The casual fan will probably never notice these things, but, like I said with the 1/4 figure, there just really is no excuse for sculpting that is this far off when other areas look so good.
The knee pads are particularly troublesome. They're made from a very soft plastic, which is good, because they won't snap, but it's also bad because they tend to bend and flex in a way that makes them look cheap and misshapen. They're also much too tight, and the way that the 'rocket darts' are set into the pads themselves is poor (I had a broken-off dart in the box). A dab of superglue will fix this problem, but it was a little frustrating. The hands are simply scaled-down versions of the 1/4 hand lineup, and as such, they lack the details on the 'quilted' fingers, as well. They're not as bad as some of the comments have suggested, and I'm REALLY happy that they got the colors correct (the 1/4 scale hands were quite inaccurate, color-wise). On the bright side, the rest of the pieces look great, from the chest armor to the boots, and another improvement over the 1/4 scale is the inclusion of ball-jointed feet, allowing for A LOT more articulation.
The jetpack hangs awkwardly, as it sits straight up against Boba Fett's back, where it should be fairly low-slung and the rocket should point slightly away from his body (seems like a small detail, but it REALLY aids in making Fett 'look' right).
The gauntlets have tremendous detail, and although they're nearly perfect, there's something about their design, or perhaps the arms, that prevents Boba Fett from holding his rifle properly. I haven't examined thoroughly, but it's noticeable in pictures I've seen, and pretty noticeable in hand. Whereas my Medicom Boba Fetts can hold the rifle naturally, as the Sideshow Fett can also, the Hot Toys version doesn't work so well.
Interestingly enough, the Hot Toys rifle is almost identical to the Medicom rifle in detail, but absolutely identical in overall size. This was true of the Sideshow/Medicom sidearms (The Empire Strikes Back versions), as well. When Boba Fett holds his rifle, because hands these days tend to be noticeably oversized, his pinky finger/palm hangs down well past the rifle grip.
The Sarlacc base is...ummmm....interesting. I'm glad I got the Deluxe version for completeness' sakes, but its just not very...great. I'm going to see about using the 1/4 scale skiff base with the figure. It looks to be perfect scale.
What I feel is that, although we now have the best 1/6 Boba Fett ever, there are still leaps and bounds to be made towards an end-all, be-all. Of course, I know we can say that about any figure. I was bursting at the seams when Hot Toys showed that pixelated photo of what turned out to be the 1/4 scale (slightly underwhelming), and the 1/6 is somewhat underwhelming as well (though it's superior in some ways to the 1/4 scale - go figure - pun intended). No company has got him right yet, though I thought that if any company did, it would be Hot Toys. So the journey continues, but in the meantime, there's A LOT to be happy about, here.
Though I'm sure this sounds like I'm nitpicking the figure to death, I really love it, and I'm looking forward to at least two more of them. I can't wait to begin hacking it up, and I'm sure there'll be plenty other members who will modify this figure and really bring out his true potential. More pictures to come.