Seriously, if you are not sure which weapon to buy, this! ^^
My team has quite a selection of rifles now from JG to ICS, CA to TM to top G&G. We still bring 2 of these and they never skipped a beat!
Light, portable, they interface with a lot of other gear. You get a nice amount of mags for these, you can then still get any weapon that uses M4/M16 mags and not have to re-buy mags.
For the price, you can't go wrong. Best weapon you can get. If you decide to get something else in the future, keep it as a reserve, or for a mate that wants to join you for a weekend or something.
EDIT: Also, these variants has the most spare parts out there
EDIT2: http://www.zerooneairsoft.com/product_info.php?products_id=6076 this is the one we carry.