My mate has one and loves it, he's taken fallow and roe with it running 120 NBTs at 2700 fps which is just shy of what I run them at in my 6.5x55 (could push them up to 3k but deer wouldn't be any more dead and more damage would occur).
I was quite tempted by one but already have 2 x 6.5s and they aren't importing the CZ527 in Grendel which would be my choice over the howa, the sporter I have handled was just a bit 'too light' for my liking but I have a thing for heavy barrels.
My middle cartridge of choice instead will be the 25-45 sharps; once I've shot through my remaining .223 ammo the cz527 will be re-barrelled with a medium weight barrel in this calibre. This will give me an all deer legal cartridge If however I didn't have a howa varmint in 6.5 creedmoor then I definitely would have gone for a varmint 6.5 grendel.
PS if you reload and you want a decent fox / long range vermin bullet and you can find them the Sierra 85gr varminters are working very well for me out of the creed, you should get them up to circa 3000 fps out of the Grendel.