Personally I played K1 first, like 2003 sort of time almost. I enjoyed it and it was a perfect fit for what would happen later on in the galaxy. Next I played K2 a year or so after it came out. It was less than enjoyable in terms of balance but has good lessons and again meshes well with the galactic events and allows you to take control of someone who is not hugely important in the galaxy.
I don't think that I really liked either better but TSL was a bit sad in that it was not complete. Now Tor ruined preexisting Canon and inn doing so my life. Lol just kidding but it does suck it messed with canon.
Savior, conqueror, hero, villain. You are all things Revan... and yet you are nothing. In the end you belong to neither the light nor the darkness. You will forever stand alone."