~27" 1440p monitors... Tempest or something else?

I bought an IPS monitor in 2008, but replaced it with a 27" 1080p 120hz Samsung in 2012. Even though the IPS looked better, the TN panel just felt like it provided a smoother (and significantly better) overall gaming experience. The IPS had decent input lag, and I don't think I'm all that sensitive to input lag anyway, so I thought it was more the faster response time.

Now I'm looking to move up to 1440p. It seemed like an Overlord Tempest would be a natural upgrade, being both IPS and the ability to overclock its refresh rate. But the refresh rate is 6ms, 1ms slower (according to manufacturer specs) than my old IPS monitor and 4ms slower than the 2ms of my TN panel. Is it possible it was more the refresh rate instead of the response time that actually made the difference? Is the Tempest my best bet?

Thanks. I've done a lot of reading there and elsewhere and I'm not sure I'm any less on the fence.

Been considering a matte, single-input QX2710 (prefer glossy but the matte seems to be glow-free - unless that was random luck). But it
- a) seems like a massive lottery (after reading about all the problems people have had with them and the other Korean monitors) and
- b) seen posts suggesting 120 Hz IPS is still significantly blurrier than 120 Hz TN - because of slower pixel response times (and, can probably only clock the QX2710 to 96 Hz). Don't really have anyway to know beforehand (since I can't see one in person) whether I'd be happy with the trade off between this and better image quality