I also have a mid-2010 MBPro.
I would NOT advise upgrading beyond 10.8.5 UNLESS you put an SSD in there.
Otherwise "running the OS" may slow down to "walking the OS", from your perspective as the user.
Actually, I would highly recommend an SSD anyway.
Cheap and VERY easy to replace in the 2010 MBPro's.
Once the SSD is in, you might even try El Capitan.
I have "test-booted" my own 2010 from ElCap on a USB flashdrive, seems to boot up and run ok.
But actually, I still use OS 10.6.8 as my "main OS' on the old MacBook.
It boots faster than any other Mac I've seen (5 seconds from Apple to finder) with an SSD inside.
Everything works "well enough" for me.
Why change?