They are pretty much polar opposite amps as far as Two Rocks go. Of course they both have that signature TR sound, but the drive channels are very different. The T3 is super smooth, and refined ODS type tone. It does have some gain on tap, but still stays smooth and relatively polite, even when the gain is dimed. Clean channel is similar but not as bright and chimey as the Gales, still has the signature TR clean sound but they are a bit darker and more 'woody'. I really like the cleans on it, and the lead for that matter, great amp.
The EG, is the most aggressive TR Ive ever played. Much more Marshall like lead channel than dumble, but still has plenty of ODS in its genetics, and has that tone that you have come to know from TR. Sounds like the thickest, richest Marshall you have heard. Dial back the gain and it can almost get into the Type 3 ballpark, but not as smooth or refined, it still retains that edginess it has. Cleans are pretty close to the Classic Reverb, somewhat similar to the T3, just brighter and more chimey. This amp sounds much better with a strat than the T3.
Definitely go with the tube rectifiers, thats part of what makes both of these amps so good.