I been djing on a pair of 1200 MK2s for over 5 years now, and I got them 3rd hand. These are built like tanks and the only things I've ever done to them include replacing the pitch sliders in each (due to dust and what have you gathering up over the years) and remove the little ball bearing which sits at 0 (on the pitch) which hence removes the 'click' one encounters when mixing on 0.
I'd suggest get a pair of 1210s MK3+, just cause they look cool in black and you can replace all the leds with another color should you want to. Replacing the RCAs would be beneficial obviously, though I don't see the point really (considering all the music was probably mixed and mastered on standard RCAs). Thats money you could spend on vinyl
The 1210s don't have the annoying click at 0 pitch aswell, and the MK3s and up have the pitch reset.