What do Crossfired R9 270's compare to?

[apalacpac]

I just built a new computer, and was able to set a set of these off craigslist from a bitcoin miner for cheap(I think, when i compare to newegg/amazon prices) - $120 total for both. I wanted something to get by, and update to a better graphics card later. I was just curios what this setup would be comparable to if I were to get one card? And how long should these GPUs work for me in the long run?

I havent overclocked them or anything.

Right now, not playing anything srs. Just playing CSGO on low settings and LOL on high.

System.
i5 4690K
Asus Z97-A
SAPPHIRE DUAL-X 100365L Radeon R9 270 2GB
EVGA New Version SuperNOVA 80 PLUS BRONZE Certified 750W
HyperX Fury Series 8GB (2 x 4GB) 240-Pin DDR3 SDRAM DDR3 1866
2 SSDs, and 1 HDD.

 

[krells]

It should be very close to a 290/290x depending on the game and if crossfire is supported.