This is going to be a debate....what one and why. Lets try to keep prices to a minimum. Make it about the product and quality not the money!
My vote is for under armour. It layers up much nicer. Scentblocker and scent lok are the same as my old field and stream jacket.
I use Scent blocker as my outer layer and i actually use under armour as my base layers. The scent blocker has worked really well for me i know people say it doesnt work well but ive had some great luck with it. I have had plenty of deer come right up under neath my tree. literally last year i had a 5 point walk right under me with out noticing me and stayed 10 to 20 yards from my tree the whole time while he was eating for about a half hour. then opening day this year i got my first deer of the season 10 yards outside of my tree. Not saying it is the reason why ive been getting my kills but ever since ive been using scent blocker ive had way more close in counters maybe its luck ive been having the past few years with this scent blocker but i never had this luck with my field and stream and wal-mart clothing. Not bashing wal-mart camo or field and stream but ive never had anything come up under neath my tree like these past few years with scent blocker and trust me i shower with all the scent free stuff and wash with it and spray with it like its a religion so that wasnt the issue. Maybe its luck but i like to actually think that this scent blocker has been working.
Of the choices you offer, I would go with UA with out a doubt... I like form fitting clothing not big baggy, sloppy fitting gear.
ScentLok because it works great to eliminate scent. Very slim gear that makes for great hunting gear.
If you wash and dry your hunting clothes and underclothes regularly with hunting soap and hunting dryer sheets and shower with hunting soap and use the hunting under arm alarm, store your stuff in a ziplock storage and change at the truck before you walk in you have no need for any of that stuff. I didn't metion a brand of soaps because they all work the same. I can honestly tell you in the last 3 seasons since I've been very consious of my scent I have yet to be busted by any deer and pigs down wind.
I love my UA gear cause it seems to layer much better than the ScentLok and is warmer. However I wear ScentLok too because I love the Vertigo pattern and I'm a fan of the carbon alloy technology. I hunt in Northern Michigan and WI so I lean towards the UA but if I hunted a warmer climate I would zip up my ScentLok! ...Not sure I helped much in this debate. haha