I think warforged are slightly sucky? They seem to make fairly dodgey wizards/clerics/druids - the power classes, easily, and in a warrior/monk incarnation, they are still woefully unable to fight character level apporiate challenges at high level - and the vaunted immunities don't seem to be an issue either
Examing a level 10 fighter, it's not like a Warforged immunities at make it a significantly better. In one on one fights Vs the 14 CR 10 monsters listed in the Monster Manual, the poison immunity has a role in 4? fights. The CR 10 fights should be split 50/50 according to the rules, and if the warforged immunities where broken, they should really shine here - However, despite the poison immunity, the warforged still
isn't going to win ANY of the poison immunity relevant fights, because they are spell casters, or grapple machines.
The most significant occassion is the Bebilith, where the things poison is going to outright slaughter most fighters via massive con damage due to the intense DC on the fort save - a single classed fighter is going to have, what, +10? Lets say he gets a +13 from somewhere - a 50/50 chance to save. However, the Bebilith is instead going to merely grapple the warforged and then rip him to peices - the Monstrous Scorpion is in much the same boat, but is also very leathal in melee combat, able to grapple and
squash the warforged.
The spell casters are not going to close and fight the warforged, they are going to keep their distance and pound him with summons and spells. Funding specalist magical gear need to deal with these suckers (flying stuff, stuff that lets you break force effects, blah,blah,blah) is going to be reduced because of the need to repair yourself.
As for level drain - fixing that is a
second level spell. Seriously, that comes free with a box of cornflakes.
So basically, warforged still lose when their ability actually matters, and then have to pay
actual money for the privledge of having immunities that at mid to high level don't make a difference.
Bottom line: Warforged make unpowered characters better, and suck if you are playing a "power concept." They probably rock really hard at levels 1-4? where getting poisoned or level drained actually still matters, but after that, well.. they suck.
