I would not trust my PC to any older Coolermaster or Thermaltake PSU. They tend to choke in competent technical reviews. The InWin is a dark horse, but with full range active PFC and 80+ certification (the chart says it doesn't have active PFC, but clearly it does) I would give it a shot long before either of the others.
And, no conspiracy. A lot has already been written about Antec's excellent offerings.
A PSU on the bottom of a case makes the case more stable, and in many cases draws its [unheated] air from beneath the case, and exhausts its warm air. An 80+ (or better) PSU does not radiate enough heat under reasonable loads to be a concern. And, it doesn't dangle excess cables into the airflow.
I know of no rule that says all gamers have to have massive heat sinks on their CPUs. CPUs have become more and more powerful, such that a point has been reached where it isn't even necessary to overclock a CPU for good performance in games. Yes, you'd need to push an Athlon II X2 260 to the limit; or take the money from the necessarily massive HSF, add it to the CPU budget, and get a X4 (possibly a Phenom II) or Core-i5 instead. If the stock cooler sucks that bad (and some certainly do), there are plenty of quiet, competent models available that would fit in the InWin case.