Base Layer recommendation

Hi guys, can you recommend some good base layer? Until now I used cheap tops and nothing on bottom as I had insulated bibs. This year changed it to shell bibs and can't imagine riding without any insulation. I see that people recommend merino. Do you use 100% or blend? I read that blend will be more durable and flexible, and will dry faster. What GSM? I got my eyes on some 180, 200, 230 and 250 g/m. Last few seasons it has been mostly between 0 and -5C here in Europe, so I guess 250 might be too warm.. Brand? Here in store I have some Mons Royale, Icebreaker, Odlo, Ortovox, Smartwool... plus some other less known or super expensive.