I was very active in paintball last year on a Rookie tournament team. I don’t play tourneys any more, but I go out every month or so to tourney practice just to keep the skills from dying completely.
I also write the user manuals for the paintball circuit boards in high-end electronic markers (just as a hobby and using no Freescale/Metrowerks resources, in case anyone from corporate is reading this), so I have some degree of knowledge about the technical aspects of paintball markers as well.
A decent paintball marker is one that will shoot accurately and consistently. For about $150, you can get a PMI Piranha STS G3 that fits the description.
http://www.pbreview.com/products/reviews/668/
http://www.pbreview.com/products/reviews/1059/
You can get all this stuff USED on ebay or from the www.pbnation.com buy/sell/trade forums for less.
A common problem with mechanical markers is chopped balls. Balls get chopped when you pull the trigger faster than the balls can be fed. This is because gravity is slow, and it’s possible to pull the trigger just as a ball is falling into the breech. When the bolt moves forward, it will chop the paintball in half and gum up the works with paint. You’ll have to field strip the marker to remove the bolt and stick a cotton swab through it to clean it properly. (We avoid this whole problem in electronic markers by using break-beam LED eyes. If the eyes don’t detect a ball snug in the chamber, the marker won’t fire).
There are several things you can do to reduce the probability or the consequences of chopping balls. You can increase the speed of the ball feeding mechanism. A gravity fed shake-and-bake hopper feds balls at about 6bps. You can get a motorized hopper for about $40 that will feed balls at about 12bps. Look for a 12volt Viewloader “Revvy” Revolution.
http://www.pbreview.com/products/reviews/111/
You can buy a non-stick ceramic barrel that will improve your accuracy and allow you to fire accurately after a chopped ball. The non-stick coating lets you “shoot-through” the broken paint until it’s all cleaned out of the barrel. You should buy a new barrel anyway, because all the stock barrels on sub $700 markers are utter shit. If you do get a Piranha marker, I would recommend the a J&J ceramic barrel with Piranha threads. Get a large bore-size, because the cheap paint you’ll want to shoot will not be perfectly round: .691 or .693. As far as length goes, 12" is perfect for most people, 14" is usable also, but 16" is just too damn long. Do not ever take the previous sentence out of context and use it against me.
http://www.pbreview.com/products/reviews/251/
You need to decided whether to get a CO2 or an air tank. I recommend air instead of CO2, even though the CO2 tanks are cheaper. Unless you only play under the Texas sun in summer, the CO2 will become colder after firing a few rapid bursts, and you will get less shots. Additionally, if you fire the marker while it’s tilted sideways or downwards, liquid CO2 will work its way up into the marker and destroy all your o-rings – yes, just like on the space shuttle (which will require you to strip your marker to replace the cracked o-rings - it’s not hard, just a nuisance)
An air system will run you about $100. For that price, you can get a 47cubic inch/4500psi tank with a high quality regulator. Larger capacities cost more. I use a 68/4500 Crossfire tank that I got for about $150. The piranha (and most other mechanical markers) takes a screw-in tank, so be sure to specify a screw mount when you order your tank.
http://www.pbreview.com/products/reviews/250/
I have tons of other opinions on this subject, but I have to finish writing another manual, so I’m going to go back to work now. Apologies for typos, I’m to tired to spell check this post. :-)
In the meantime, go to www.pbreview.com and check out all the product reviews.
If you’re wondering what I shoot, I have an AKALMP Viking with eyes and Chaos Pandora circuitry, a custom trigger, a Halo B force-fed loader, and a carbon fiber barrel. Before that, I shot a PMI Piranha STS for 2 years. I kept it as my back up marker until I sold it to a co-worker’s grandson a couple months ago.[/b]