My inexperienced view...
I really like the earlier E designs, the 27, 29, 32-2 and 35-2, although this is probably because they are the ones in my price range.

However, when looking at them practically, in terms of cockpit and cabin space and LWL, it seems there are diminishing returns as you go up the size range, but I suppose this is probably true of the newer designs also. This is mostly based on studying the boats at the dock, and from drawings, as I have only been aboard a few 29s, not any of the other models.
If you don't need/want a U shaped dinette, then the 27 offers a remarkable amount of amenities for its size. IB or OB engine options, and mostly tiller steering.
The 29 just stretches the 27 out a bit, with a wider, almost double quarterberth (unless the engine lid has been raised), and always comes with an inboard; models after '75 have standard binnacle steering.
The 32-2 gets you a U shaped dinette, but not much else over the 29. The displacement is only 300lbs more, and the LWL only 2' longer than the 29. Some of the extra length is in overhangs which don't contribute much to LWL or space.
The 35-2 just stretches the 32 design a bit more, with a bit more space everywhere, but also more pronounced overhangs, and less than 2' increase in LWL, and only a few inches more beam than the 32-2.
The 27 and 29 may appear a bit stubby with shorter overhangs, but offer the best bang for the buck in terms of usable space in the cockpit and cabin areas, and both offer good foredeck access compared with other makes in this size.
The 32-2 and 35-2 are both very graceful designs with long overhangs, but with the prices generally 2-3x the price of a 29 in similar condition, offer less value overall.
I think the pricing has a lot to do with perception, and which side of the magic 30' line the boat sits. As all of these boats approach the 50 year mark, it will be harder to justify a price comparable to boats built and designed in the late 70s/early 80s, which offer *much* more usable space, and usually sailing performance, at similar prices. For example, the 80s Ericson 30+ sells for about the same as a 70s 32-2 in similar condition, but offers more space all around thanks to wider beam and shorter overhangs, and also a lower PHRF rating. Likewise, the 32-3 compares similarly with the older 35-2.
Those with more experience than me (which is pretty much everyone here...) may offer some corrections, but these are my thoughts based on far too much couch sailing, and not nearly enough real sailing...
btw, I use the following to compare PHRF ratings to get a rough idea of where a boat sits in its class:
http://solovalcour.com/doc/PHRF.pdf