So, the F540s are pretty good. The first thing you'll notice out of the box is how stunningly cheap the plastic looks. It seems well built enough, not as light and flimsy as TB...but just the materials itself just seem low budget. And that's fine, cause they clearly put more resources towards everything else.
Sound quality is decent, what you should expect out of a $99 headset. Bass is present, but not overwhelming. Better overall balance than the TBs or the primers. The amps are strong enough that it doesn't distort as at decent volume like the primers either. The TBs might have the edge in overall clarity, but they're more expensive too. Definitely beats the primers in all areas of SQ.
The wireless is good, theres no constant audible whine or hiss like the primers. It's 2.4ghz but I had it right near my router and there were zero issues. Having multiple inputs is definitely a plus. There's no surround processing, so you have to bring your own, and that's such an important feature that you should probably spend more on something that can provide it, if you can't. That's probably a dealbreaker for most.
Very comfortable too. Nice and light, pads fit comfortable around your ears, instead of on top like the primers. They don't squeeze your head either.
Overall, they beat the primers hands down in every area. Not even a competition. The dets/warhead have stronger bass, but the clarity is about equal. Build quality is lower than tritton, but it makes up for it in comfort.
Of course it requires the dreaded chat cable, so take that into consideration, but for $99....I don't think they can be beat. There's nothing else like it in that price range that's nearly as good.
One thing I noticed is that when the mic isn't muted, it has sidetone/voice monitoring always on. That's fine if you're using them in a quiet room, but if you're using them in a noisy room, you have no way to turn it off without cutting off the mic entirely. Not an issue for me though.