Danny,
Some of Life-Like's sets are better than others, from what I understand. Here is a list of the sets that they currently produce:
Little Joe - Comes with an 0-6-0T engine. This engine is probably fine for running around in circles, but it probably doesn't work well if your layout has switches/turnouts. The is because of the short wheelbase--it can't reliably pick up current over the insulated frogs of the turnouts.
Diesel Charger - According to
Spookshow, the GP38-2 included in this set is supposed to be a pretty decent locomotive.
Freight King - The GP20 used in this set is widely considered to be a good locomotive.
Micro-Trains uses it in a couple of their train sets (Hershey's and Pepsi Cola collector's sets).
Diesel Transport - I've heard from different sources that the SD7/9 is one of the best bargains available in N-scale. Check out Spookshow's
comments on it. I'd like to get one of these engines myself.
Yard Master - The new one comes with the SW9/1200. This is widely considered to be the best switcher engine available in N-scale. I've got one and it's fantastic. It's so small, but it runs very smoothly, even over the turnouts.
The sets come with nice rolling stock, and most (if not all) come with their Power-Loc track. Some sets also come with kits of buildings. All come with power supplies (except the Micro-Trains sets), but these are the cheap kind. I'd invest in a better power supply (like one made by
MRC). A decent power supply will make a HUGE different in the operation of your locomotives. Those cheap ones generally only have two speeds: stop and too fast!
I hope this is useful!
-Rory