I picked my self up a SL94! now just got to look into getting a new hopper and gas bottle and maybe a new mask!Pretty much all guns are reliable these days and require very little in terms of upkeep, but as said planet guns are renowned for their "chuck in the bag ability"
If your in the market for good price guns to start out with and hold your own then check out;
Geo/Ego
DM series
Mini/Axe
Old school cool-shockers, PM8 and older DMs and egos (as well as Eteks) still hold up well in this day and age and are very cheap