I have a 'firm' Bridgestone set which I got after putting 15K on my originals. I have put 25K on my new set, the Bridgestones, and am very pleased at their life. I get them rotated and balanced every 5K. I recommend having that done at the tire dealer. I am expecting at least another 25K at the current wear rate. You can look for my prior posting a long time ago. Also, make sure your alignment is good. The dealer aligned my wheels incorrectly and I had to have it redone. This can cause bad tire wear!
I'd second your comments - replaced our Goodyears at just under 20,000 with Bridgestone Alenzas - we're coming up on 50,000 miles (30K on tires) and at the last service Lexus measured 7/32nds - should easily see another 25,000 on them. We also get alignments every 5,000 at Firestone with their lifetime alignment plan.