I'm a big fan of Feathers and Astras, but there's a big price difference between them! Feathers are sharper, and some people find them harsh, but for me they're super smooth, for four shaves. Astras I can get slightly more shaves out of and they cost much less.
I also like Super Iridiums.
Astra SP, Gillette 7 O'Clock SP (blues or blacks), Red IP's, Crystals (Blue IP's), Feathers. These are the blades I've bought 100 or more of.... they all work nicely for me.
Hard to go wrong with the Astras. I just received some Gillette Silver Blues and those are very nice as well. I generally am not a fan of the 7 O'Clock series but the GSBs are, so far, outstanding
I really like my Astra SP blades, can't go wrong with them. I was looking for something close to Feather sharp but smoother and went with GSB (Gillette Silver Blue) blades.
I heard good things about the Super Iridiums but thought they were discontinued?
Agree 100%. Don't commit until you have sampled around. Different blades work better in some razors than others, and YMMV as always on blade choice. Committing to a bulk buy of one type just locks you in before you know what you really like...