Today i bought 10,000 SP (8.99 USD) i bought a mask which gives 40k, as well as a 7 day axe and a 7 day 150% exp item.
My judgment: 100%
worth it!
With the 40k i bought a D. Eagle, then when i ranked to staff seargent (OH YEA) I bought an AWM.
The D. Eagle is GREAT. The accuracy is there, as well as the power. Usually 3 shots to take out an enemy.
The AWM is even MORE great! 100% accurate and 100% powerful. A must have.
Then, the almighty axe. To be honest, for about the first two hours playing GM with it, i was disappointed.
I was constantly killed and it seemed like the axe couldn't kill a fly. Then, i started to get the timing down, and HOLY CHRIST! i was murdering GR! Next i started using the axe in S&D and T.D. It works like a charm. 100% recommended.
So in conclusion: Invest 9 dollars! You won't be disappointed! Trust me. =]
P.S. I would only recommend the 150% exp to people that are active (to get there money's worth) and that are pretty good. During one of my games, i received about 300 exp and with the 150% exp it added another 150. But if you suck and can't manage past 100 exp per game, you aren't getting much out of it.