The 2011 MBPs have S-ATA 6.0Gbps, which is often just called S-ATA III (III = 3).
www.everymac.com can show you, or any of the hundreds of threads here dealing with that.
but some ppl complain that they still have SATA 2?
AFAIK That is only in the optibay (where the optical drive goes), but the newer april/may models are shipping with SATA III in the optibay.
but the models before that have SATA 3 in the hard drive bay right?
All 2011 MBP's have SATA 3 in the main HDD spot. Some have SATA 3 in the optical spot, some have SATA 2 in the optical spot. The 2011 model is the first to have SATA 3.
how do you tell the difference?
Check the "link speed" in system profiler - they should both show 6g.
Check the "link speed" in system profiler - they should both show 6g.
hmm, do you have to be dead-lucky on this or is there a 50/50 chance?
With your vertex 3 have you got TRIM enabled? With 6GB/s?
No, not anymore. I tried it and I got a few spinning wheels, so I turned it off and it's back to normal (normal = everything opening instantly!) The Sandforce drives have their own TRIM alternative built in anyway. Additionally, I've heard you can leave Windows 7 running overnight and since it has TRIM, it will do garbage collection at that time.
Does the GC work well by itself?
50/50
I'm not sure how I would be able to tell. My drive is <50% full and <2 months old, so it's never been a problem. From what I've read though, the Sandforce GC is very good. Hopefully TRIM will be enabled in Lion so it'll be a non-issue.
Hm, anybody know the success rate of getting a fully-enabled SATA 3 MBP (13") when you purchase it online? I can only assume that the stock used for Apple's online store is moved a lot faster than any one Apple store, thus it's probable that the newest silent revisions are available there first.