I don't wear synthetics at all anymore. Merino is softer, wicks sweat better, feels warmer while drying, and best of all doesn't seem to stink even after a week or more in the field --don't get me wrong, I stink, just not my base layer I have been pleased with products by icebreaker and stoic, as well as I/O Bio and even smartwool. I keep my eyes open, and shop deals when I can. Even my socks and underwear are merino these days...
A little of each for me. For archery i pack an extra shirt or two each day to trade out as the sweat accumulates. Come October/November with the cooler temps I tend to use the merino more, whether it is KUIU or smartwool. I'm kind of a base layer guy picking up something new about every year whether i need it or not.
For base layer - have moved for the last 4-5 years to mostly all Merino or silk, other than sometimes Wigwam Ultimax liner socks under my merino socks. Have worn synthetic underpants/ boxers for years even when wearing merino and silk other layers. Now, this past year went to Merino Boxers, and do not know why I waited so long.- Other than being too cheap to spend 35-50 dollars on a pair of undies when I had so many synthetic undies.
Are there any positives to synthetic? All merino for me. Sometimes its nice to wear poly though when the suns really beating you on the prarie. But when its that hot, ill just take some ash from my kifaru stove, take my shirt off, and give myself my own vias camo