As far as warlocks and DFAs go, the DFA gets 4 less (or 2/3 as many) invocations than a warlock. However, the DFA gets additional breath effects at levels 2, 5, 10, 12, 15, and 20th levels which means they're effectively ahead by 2 because the warlock has to spend an invocation to change his Eldritch Blast since Blast Shapes/Essences are invocations.
When I re-viewed it yesterday, I was only really looking up to the point that I'd played them. The Breath Effects are "traded" for Invocations at levels 2, 5, 10, 15, and 20, but the level 12 one is free, and the DFA slips in an extra Invocation at certain levels (even at level 3 they're ahead). If I only looked at that, it would seem like Extra Invocation as a bonus feat at 6 & 12 would balance them.
But it doesn't. My DFA could CC / BFC great; Warlock, not really. DFA gets a better skill list, more skill points, better HD, and good Fort; the Warlock gets... better BAB. Oh, and SAD v. MAD
So the assertion I made (in haste) yesterday about the classes being matched, should really have just been met with:
Thusly, I stole the second sentence of SirPercivals re-write from H.A. and added it onto my own. Which now means mine is the exact same as his.
Also, you get 1 blast shape or eldritch essence every 3rd level (3,6,9,etc). EB still counts as an SLA for feat purposes (e.g., Quicken SLA).