Having used my share of air coolers, I can say that Thermalright builds quality products that aren't far off Noctua in the heatsink department.
The fans aren't necessarily the best, but they're more than ample and obviously can be replaced.
I would recommend the Thermalright Phantom Spirit, it's basically the same thing as the Peerless Assassin but with an extra heatpipe for the same price (£30ish).
For those on a tight budget, there's also a five heatpipe (vs four) version of their Assassin King cooler for £15.