I'll try to add something from my side for bit more objective view on things.
Easiest is to say which semi's NOT to get:
Mad Galil (capsule) ( Overall SUCKS except for some few CO-OPs )
Galil This sucks even more
MSG5A1 This is also VERY bad
IMI99SR This thing seems to inherit some of the worst qualities from other semis... this is basically like a little dog, makes lotsa noize but doesn't have a bite to follow up. Weak DMG, SLOW ROF
Now the Actual semi's:
*SR-25 ( trainer described it well ) I would advise you trying it a few times before buying. For my taste... it's 2 much like a bolt-action. Slow shots, chance to one-hit that you'll be relying on.
*Walther-WA2000 ( this f**king thing is bloody expensive... 58 000 for gun + 10k for mods ) You get something like 6/12 ammo. I feel this thing has been made in Belgium, total rip-off on the price tag and what it offers. However it does have 1 of the highest 1 hit KO's .. it has close to no-moveshot tho... ROF sucks too and recoil reminds you of the saiga.
*HK-417 this is what I see as a semi... very low recoil, somewhat fast ROF... it will almost NEVER 1-shot... but it will ALMOST ALWAYS 2-shot. Very reliable in this sence. Has only 10 ammo in a clip though and rare times when it takes 3 shots might make you upset. Excellent moveshot btw!
* Borte chino (capsule) dunno anything about it, except that it doesn't 1 shot as often as SR-25, it supposedly has slow Rate of fire, and some recoil
* Zebra ( capsule ) - best capsule semi-sniper u can buy. Something like a cross-over of SR-25 and HK-417 ( 10 bullets, no recoil... EXCELLENT moveshot and ROF and it can actually sometimes 1-shot.. or if not leaves enemy lit ) Overall I would call this 1 of the best semis.
Best Semi: Zebra SVD ( capsule though ),
non-capsule you gotta decide between: SR-25 and HK-417 ...
I like HK417, trainer and some other prefer SR-25.