Progressive Options has provided more great cuts in LA than just about anyone over the last few years. BUT... recently they've been screwing up orders and their selection has been a fraction of what it was. They had some serious issues a few months back and they haven't recovered.
LA Wonderland is my current pick, though I'm always looking for new sources of interesting and stable genetics.
Tips for picking cuts? Healthy green, no discoloration or matte smudges on the leaflets. No clipped leaves, since it always makes me suspicious that they're trimming away their problems, rather than fixing them. Find out what days they treat, then come in three days later. Re-treat them when you get home. Personally, I like to sulfur the heck out of new cuts. Actually, I hit em with everything but nuclear radiation and DDT. Anybody got a line on a cheap gamma source? Just kidding.