Boy do I. The PR4GT is a solid tire that has comparable grip to the T-30 GT and T-30 EVO GT. The original T-30 GT has a very direct steering feel and turns/steers quickly but has excellent stability at the same time. The Michelin PR4GT has a less direct steering feel and turns in and steers somewhat slower than the T-30 GT. The new T-30 EVO GT slides right in the middle of the other 2. Bridgestone claims the EVO series has an improved contact patch and rubber compound that improves overall handling/steering and significantly improves the tires wet weather performance (more later). My favorite all-out sport/performance tire would be the original T-30GT with the EVO 2nd and the Michelin 3rd but they are all so close there is no real speed advantage to either one. The original T-30s are just more "playful". All 3 are great handling tires that allow you light the underside of the ST on fire if you want (I have had to put water on my smoldering lower right-side fairing a couple of times).
The PR4GT, and PR3 series before it, has long been the gold standard for wet traction, a claim which I have proven over many many miles on other bikes I have owned with PR4s. I finally rain tested the EVOs on my ST1300 a couple of weeks ago and they have a very similar glued-down feel on wet pavement but one ride does not a test make. I read one independent test that claimed the new EVO is the match for the PR4GT in wet grip so maybe Bridgestone has closed the gap with Michelin.
Lastly there is wear. When ridden on my test track, The Appalachian Mountains, I get around 15% of the miles you can expect out of a set of tires. The all-time rear tire "mountain" mileage king has been the PR4GT which lasted 2,038 miles. The best mountain tested T-30 GT was 1540 miles and my first T-30 EVO GT did a combined Highway/Mountain "test" of 3017 miles but it had 200 miles left in it when I threw on some Pirelli Angel GTs for some spring testing. The mountain test portion on the EVOs was right at 1,500 miles so the new T-30 EVO GT seems to wear better than the old T-30 GTs.
I given you rear tire only performance because I believe the front tires from both brands wear out at nearly the same rate. With my upgraded front suspension on the ST I can get almost 5K out of a T-30 GT in the mountains and it looks like the EVO gets about 25% better yet. The PR4GT fronts can go slightly longer but I find that they lose their feel and steering feel as they near end of life. The Bridgestone T-30 GT and T-30 EVO GT are the gold standard as far as front tires go on the ST....to me. Unmatched precision and stability with outstanding light-to-the-touch turn-in. The EVO has lost a little of the directness but the better wear redeems it in my book.
T-30 EVO GT is my current first choice but you can't go wrong with any of them. The Bridgestones are significantly less expensive but under most riders the Michelins may give a few more miles so if you don't change your own tires the more expensive PR4GTs may still be close in cost per mile when you add shop expense. I have my own tire changing equipment that has paid for itself more than twice in the last 4 years.
For the record I have gone through 10 rear tires on the ST (some darkside/Night Dragon testing) in the last year so I feel my information is reasonable accurate. I have no ties to any manufacturer and compare notes with all my friends that ride at my pace, which in the case of the ST is really just one guy and his notes are terrible. But he is fast as hell so I just fact check his data when he's around. Sorry BR but I do respect the fact you have a life that doesn't revolve around motorcycle tires.
The one thing I can add to the Bridgestone (and Dunlop or whatever brand)/Michelin debate is I have had several of my friends tell me they prefer Michelins to Bridgestones because they feel they grip better. I have noticed that, to a rider, these guys always ride a little faster on the Bridgestones (or Dunlop sport tires) than they do on the Michelins. I have always thought the easier turn-in and lighter overall feel of the late model Bridgestones allow most riders to go faster with less effort and the slightly higher speeds means more moments where the front pushes and gives the feeling of lower traction. My opinion, I could be wrong.
There, aren't you glad you asked Ike?