Neither of those other two turntables has the potential of your Lenco. Keep it. You will be sorry, otherwise. Like Dave said, get rid of the stock tonearm, and that's half the battle. Here is a link to what might be a good candidate to replace the tonearm, for very reasonable bucks:
http://www.designbuildlisten.com/wand.htm
Or there are any number of fine vintage tonearms that can be had for similar expense, e.g., Victor, Sony.
http://www.designbuildlisten.com/wand.htm
Or there are any number of fine vintage tonearms that can be had for similar expense, e.g., Victor, Sony.