SSD's are great if you can afford to drop $400-$500 on storage, if you want any decent amount of space.(512GB)
I would more than happily get a 256GB, but after partitioning, it just isn't worth the lack of space. Even the 750GB hybrid is significantly cheaper than even the 256GB SSD.
I think hybrids are good median ground, it may not be as fast as a pure SSD, but for the average user it's going to make a huge difference either way, especially if you coming from a 5400rpm drive like the OP is.
240GB SSD's are $150 right now (was a deal on a Sammy 840 yesterday, with a free game). Also putting your HDD in the optibay is a no brainer.
Who the hell needs extra 250GB of space on an SSD for a 13" laptop? First 100GB for Apps and OS, fine, I understand, then you have 150GB more space for other stuff...then you have your stock HDD (750GB?) in the Optibay...that's a gig worth of storage.
512GB SSD's are not worth it right now and don't make sense, unless you do a lot of video work and need to capture high datarate video...but on a 13" laptop? C'mon.
Although the 2012 MBP13 Supports 6Gbps, you will find the link speed for the stock 500GB drive negotiates at 3Gbps. See here
Image
Seems like that HDD is a
SATAII HDD, so that's why it's not running at SATAIII.
So in other words, the optibay on the 2012 will definitely support a SATAIII device like an SSD drive.
I know for a fact that the 2011 MBP didn't support SATAIII speeds in the optibay. Ivy Bridge transition must have fixed that.