I just got my Spikes upper last week and it sports the SAR rail. I like it light, the kinda oval shape lets the hand wrap around nicely too. Rifle ended up right at 8 lbs even.
Though I haven't had it long enough to find anything I don't like either so take it for what it's worth. I can get up pics tomorrow if you want or have questions on anything with the rail.
That said I got it cuz it's all I could get at the time. I do like the tubes with the add on rails. The rail space is nice to adjust things where you want but I was never a big fan on the quad rail look.