I've been super happy with my 10. I have it on a plate so it clips on to my leveling base that I shoot off of, which is super nice for glassing as well.
The 20 has a leveling base built in, but looks to be the same pan/tilt fluid head otherwise. I do really like having the ability to plop the tripod down and not have to monkey with getting the apex level to make the pan head work well (especially on steep terrain).
Do you plan to clip a rifle into this tripod? What legs are you getting? What optics do you need to support? I don't use anything bigger or heavier than my Kowa 66mm spotter, if I had a big 99 or maybe even 80 I might consider something with a bit more beef.
If yes to shooting, I would 100% set up in some manner as I have (Anvil or leveling base on the tripod, pan head clips in to that). If no to shooting, the 20 with built in leveling would be really nice (though I haven't looked to see how much weight it adds).
