My main problem with ECLs myself is that, as you know, it hurts some classes more than other. From least hurted to most hurted, we have Fighter, Barbarian, Ranger, Paladin, Rogue, Monk, Cleric, Druid, Psychic Warrior, Bard, Wizard, Psion, Sorcerer. (Rough estimate only, OK.)
Even if you play something which has innate spellcasting class levels (like, say, a Dragon) that stacks with your own class levels, you will miss greatly from the lost levels. For a purely fighting class, the lost levels can be made up by Strength, as demonstrated by Ghorgor (off-topic: Ghorgor Bey has a nose-ring of regeneration, IIRC). But when it comes as a trade-off between casting 3rd level spells and casting 5th level spells; the gap is harder to swallow.
My brother played a shade sorcerer shadow adept. With ECL +2. His character died, for lack of HD. And wasn't very effective, for lack of spells (the level penalty of the ECL, combined with the one of the sorcerer, is especially harsh). A normal human wizard of the same level would be two spell levels ahead -- and that's always a great boon, from 1st-vs.-3rd difference to a 7th-vs.-9th difference. Even worse, a druid reincarnated this character, and rolled a Centaur. So, now, this character has lost a level (for reincarnation), and has a worse ECL. Stealth -- the greatest strength of the character, after spellcasting -- is severely impaired. On the other hand, that PC can now run away really fast -- and that is how she adventure now.
(This raise also the problem of reincarnation and templates, do you keep them or do you lose them ? Some are obvious, any undead template is lost, for example, but for some other it's harder to say. But that's off-discussion here.)
