Tower giants have about 50-100 more ac, maybe a little more, and about the same boost to attack, and probably 20-100% more hitpoints, making them do over time, 21-102% more damage per giant.
That being said, I soloed my way up to the named areas on occasion, as a 76 beastlord, all gnollish, decent AC augments(polished caracite, and reworked heavy steamplate whatever, then the hotzone augs with 10+ ac or 50+ hitpoints and resists) with two CoA augments, a 45% haste ring from DoN, some other miscellaneous stuff, basically I'ld equate myself to CoA geared. I've only got 412 aas, none of my 'big' 74 or 75 spells. If I grab direwild skin from my druid, I can self buff to 14.5K hitpoints before growl of the leapord (DoN crystals... don't have any upgrade yet.))