I like the 7 o'clocks (both yellow and black), and the Asta superiors very much, the Super Iridiums I haven't gotten a great shave with yet, however many folks love them.
YMMV is very in effect as I'm not a particular fan of Derbys either, I can only use them in one particular razor to get a decent shave.
I've heard (read) folks compare the Astras and Iridiums favorably to each other, but I've had different experience so far.
Your best course of action would be to acquire some samples of each to try.
I'll send you some Astras if you'll PM me your address, maybe someone has some Iridiums to let you try
After Monday and Tuesday, even the rest of the week goes W T F