This was my first paintball marker. This is a great marker for beginners just getting into the sport, or as a lower-end backup. Because of Spyder's basic blowback design, this is a great learning tool for beginning players. It is fairly simple to disassemble and clean, and is the perfect introduction to new players for field stripping a marker. Another plus to the basic design, is the fact that there is hardly anything that can go wrong on it. Most major issues are easily diagnosed and fixed, which makes it an easy marker to maintain.
As far as upgradibility goes, it's a Spyder. For those of you that aren't too familiar, Spyder is one of, if not THE most upgradable style of markers. Basically everything on this marker can be swapped out or added on to, all the way up to making it an upper class marker with the right upgrades.
Overall a great marker for beginners, or as a backup or project marker.