Before buying anything, I would listen to a couple of podcasts with John Barklow from Sitka. He did a couple of outstanding podcasts with Snyder (Kifarucast) as well as with Randy Newberg (cannot remember if it was Hunt Talk or Elk Talk) and even a couple of NockOn podcasts. Anyhow, even though he works for Sitka, the information about "building a system" is universal to whatever clothing you buy. A lot of people are "Sitka guys" or "First Lite" guys etc...I would recommend building a system that is custom tailored to what it is you are doing and how you will be applying it and dont care about the brand and/or mixing things up. Both companies have pieces that work better than others at times depending on application. Think about wool vs. synthetic, brush busting vs sitting in a treestand etc and how you will be utilizing your clothing. I have a hodgepodge of Sitka and Firstlite that I wear and feel 100% confident in the application and know how it will work when I go out into the field. In my opinion, you CANNOT go wrong with First Lite or Sitka. I have had both in miserable conditions and I honestly dont have one bad thing to say about either. Any type of failure/rip/tear has been a result of a situation that any hunting apparel would have failed (ie. miles of AZ catclaw that only thick carharts would have survived).
I feel like I have missed out over the years because I get excited and simply buy something that looks freaking awesome, but after a couple years looking back, I have only used the piece a couple of times because it just didnt really fit into the layering "system" that I run. Start with what will be touching your skin and then move out from there. It is all personal too. I run first lite baselayers from the waist down (boxers/leggings...a variety of thicknesses based off of where i will be going/what I will be doing) but run Sitka Ascent or Apex pants, a Sitka Core lightweight hoody, sitka midweight fleece as a second layer and then a uncompaghre jacket from FL that I love more than anything. I also have a flash pullover from Sitka in case of a downpour/intermittent weather. I do not run any real rain gear at this point as I have never hunted in an area or season that needs it.
Sorry for the long post, I just feel partial to people sticking with a specific company just for the sake of being a fill in the blank "guy" who has all matching camo. So much good clothing right now, especially with the two you are looking at, and if you can build something specific for you, it is even better. Hope that helps.