A few weekends ago, a buddy of mine went to the Ferry game in Abbotsford, B.C. and played with a Tanaka M700 AICS. He was on the opposite end of the ferry and could hit the other end of the ferry. I can't remember how many meters that was, have to ask him and repost. But it is possible hitting long ranges with high powered bolt action sniper rifles.
Depending how big your field is, the SR-25 would be a good choice if you went the AEG way.
http://www.wgcshop.com/WGC_Shop/imag...r25cnc_low.jpg
Although it could prove to be combersome in tight quarters, but if you're playing in tight quarters such as an indoor field, use your sidearm.
But like Greylocks suggested, go to a game and rent some guns before buying anything. If someone at your field has either a AEG or Bolt Action Sniper rifle, ask if you could take a few shots. That way you can decide which is better for you.
Good luck in your search and have fun with whatever choice you decide with.