While the 2010 series are not the fastest, installing a good quality (major brand) SSD and maxing the ram (up to 16GB) make a huge difference to performance. As others have said, the SSD will make the biggest improvement, but everything helps. Before I did the upgrades, my late 2011 17" 2.4 i7 was infuriatingly slow (I think the original drive was faulty as speed tests would only result in 40-45MBs), but now the only reason I would consider a new MBP is for a retina screen and the ability to natively run a 4-5K monitor, and then only the 2013-2015 as the SSDs are still replaceable on them.
The geekbench scores now are over 11000 with over 500MBs for the sandisk ultra II that was 2/3 the price of the Samsung, and I was lucky enough to get 16GB of 1600MHz Crucial ram for $69 last year. My memory monitor shows all the ram being used/reserved all the time (as it should be - unused ram is a waste) so while 8GB is a huge upgrade over the pathetic original supplied, 16 is not wasted, although it will consume more power if that is an issue for you.
Another somewhat riskier improvement to performance and lifespan is cleaning and replacing the heatsink compound on the CPU, and if you're keen, polishing the CPU first to improve the heat transfer. I'm not kidding, check out youtoob.
The Unibody MBPs are surprisingly upgradable devices and the later ones can deliver amazing performance and utility (the 17"s still had a PC express slot that will take various cards like USB3 or SD card reader, etc) and the airport/Bluetooth can be upgraded to support handoff, never mind essentially unlimited SSD storage when you swap out optical drive. Imagine ordering a new MBP with 4TB. Even though they supply super fast drives, you could do it for around $1200 and RAID them.
Unless money is super tight, I don't think the marginal savings in getting SATA 2 over 3 are justified as they can always be reused in other devices or external drives at some stage.