Of those 2 I'd go with the BenQ because it offers blur reduction. You also might consider the Acer XF270HU. It's IPS with 144Hz Freesync, but no blur reduction. It's the one I would go with, but maybe you prefer the faster TN screens to the Better IQ (but slower) of the IPS.
I believe that a lot of the issues with the MG279Q and similar were with the initial production runs and quality has gotten better over time, but I'm not 100% sure.
Why not save some cash over the XL2730Z and get the Acer XG270HU?
Review:
http://www.tftcentral.co.uk/reviews/acer_xg270hu.htm
XG270HU is $70 than the XL2730Z on newegg at $469.
http://www.newegg.com/Product/Product.aspx?Item=N82E16824009769&cm_re=xg270hu-_-24-009-769-_-Product
MG279Q would undoubtedly result in a better experience than both the BenQ and the Acer. IPS 144Hz is no joke. Think the MG279Q can be had for $599 right now.
Only one Acer 27" model is available (Acer K272HLbid) and it does not have Freesync.
If buying local this is a no brainer. Get the MG279Q. I own it and it's pretty amazing. Best monitor for the price and Freesync deserves the hype. Don't let the 90Hz max Freesync range throw you off either. After 90Hz it really doesn't matter much but with some work you can change the Freesync range from 35-90 to 60-144Hz if you're inclined to do so. With one 290 you won't really have the power to take advantage of the higher ranges at 1440P in modern games.
TN is really the worst option. They're way over priced for what they offer. And at 27" colour shifting will be super obvious and is much more distractingly annoying than a little IPS glow. Also many 144Hz TN panels suffer from pixel overshoot as they have very aggressive overdrive settings which the IPS MG279Q doesn't suffer from.
My 2 cents.
Oh and small sample size but both my friend and I bought from Newegg around 2 months apart and both have early panels but we have no dead pixel or major IPS glow issues many are complaining about.
That being said any monitor you buy today is a gamble though. QC has gone down for both Acer and Asus. Not sure about BenQ or AOC but a quick look at NewEgg shows they're not expempt from QC issues either. Buying local is smart if you have the option.
Good luck.
I'll either try get the 279q from a local store that has a good CS, or wait for future models hoping that they will have less QC issues.
Thanks for your help.