Well, since you're just getting into this I agree that you probably want to buy a rig with a working cartridge that's already set up, that way you don't have to do all the mounting and aligning yourself. The cartridge and the stylus are seperate and you can have a cartridge retipped (given a new stylus) but it's rather pricey. If you can find a used unit where the cartridge and stylus have low hours and are said to be in good condition, then just check the sellers feedback. Most (but this doesn't always hold) sellers here are just like you and aren't looking to sell you a piece of junk. If you get a really good deal on a used table but the cartridge isn't included or isn't up to snuff, then I'd still buy it because you could always find someone to mount a new cartridge (or really, do it yourself, it's not that hard) and then you have the added fun of getting to shop for a cartridge. (maybe I am a glutton for pain).
What you'll find if you do like vinyl is that you may decide to switch your cartridge way before it dies out, because the cartridge alone dictates much of the sound, and there are so many different types, ranging from 50 bucks up to 100,000. The stock MMF-7 comes with a Goldring Eroica (a very competent cartridge). If you started with the MMF-7 (read the reviews in the absolute sound and elsewhere, because it does compare with all the $2,000 rigs and some higher than that) then you would have to spend much more to hear significant difference in sound. Same thing with the VPI Scout, but the scout you can send back to VPI for upgrades as you desire.