I've tried quite a few and I'll be sticking with megs endurance tyre gel as it looks good (slightly too much gloss if I was being picky), lasts a long time, but mainly because its cheap-ish and a bottle lasts forever. Compared to autoglym tyre foam it must cost a fraction of the price per application, and doesn't result in "tyre browning".
Chemical guys new look gel is also recommended, although I haven't tried it myself.