I also used have used the Promaster 525T and 6160 head I bought from S&S archery. It has worked very well and I've been happy with it. When packing meat out one leg unscrews and can be used as a hiking pole also which can come in handy. Only disadvantage I saw to the twist lock so far is it got gritty on a windy antelope hunt from blowing grit. It wasn't that big of a deal, it functioned alright.
I bought an Outdoorsmans compact medium tripod this fall and it's great if you don't need to stand. I love their heads and quick attach system. If you buy from them call them and let them help you decide what fits you best. They talked me into the panner for use with the pistol grip head and I'm very glad they did. The quick attach and rifle rest let me stop carrying separate shooting sticks too. Buying things together over the phone they also gave me a discount.
I was going to sell my Promaster and get an Outdoorsmans tall tripod also, but figured out with the added height of the panner, pistol grip mount and bino mount I can stand with it using my 15x Swaros as long as I'm not glassing uphill. It's tall enough to use either Outdoorsmans head with my angled spotter. I ended up just ordering a spare panner and tripod mount from Outdoorsmans so all my accessories and glass interchange. If I need standing height I'll take the Promaster, if not I'll use the Outdoorsmans. The weights of the tripods are almost identical and the compacted heights is not that much different. Between them I should be good for about any situation. The Outdoorsmans tripod is aluminum and seems steadier at an equivalent height.