The Smart Parts Ion is a great electronic starter gun. Even without an upgraded board, it'll keep up with any electric hopper you have. The Ion can be had for cheaper now due to the new Proto Rails being the standard starter gun this year. It's a great buy for ~$100 without upgrades, since slower, unreliable Tippmann 98 customs cost ~$75. I've had consistent fire from this gun and the gas valve is easy to adjust. The only problem I've had is the loss of pressure if I fire too many shots consecutively but rarely would you have such a problem and some of it may be due to your tank or hose.
A recommended upgrade is a set of smaller barrels since any gun tends to curve balls sometimes without one. With a constant and reliable nitro air tank, you'll be able to snipe opponents with ease.