The most popular type of snooker cue sold these days is the 3 piece snooker cue. But be careful, there are 2 types of 3 piece cue around. The first type is the 3/4 split cue that comes with a smart extender. The smart extender is a small, typically 6 inch extension that screws into the base of the cue to give that little extra reach when plying rest shots, and is very popular especially with the pros in the tournaments.
The second type of 3 piece snooker cue is again a 3/4 split cue with a 20-30 inch extension. This extension fits in between the butt and shaft and considerably increases the length of the cue. This makes the cue almost the same size as the "long tackle" cues that live under the table, sag in the middle and which everyone hates to use. This sort of extension is for those long rest shots; the advantage of this set-up is that you are using your own cue with a superior tip to make those shots, so theoretically you will make a better shot as you are using a cue you know. I know its only theory, but all the same you will probably be better off using your own cue rather than those tatty long reach cues that come with the table.
So really the best idea is to get a 3 piece snooker cue that comes with either the smart extender or the long extension and get the other type as well. So then you have the best of both worlds and now have a 4 piece cue. But be careful to get the extension that works with your cue, there are at least 2 standards of screw thread out there. If in doubt ask your supplier which extensions will fit your cue and be sure to get a cue case that will fit all 4 pieces.