Godox wins because of high spec and performance, VFM, large product range, and everything compatible with the same excellent trigger/controller system, including speedlights. No other brand has all those things.
Working outdoors in bright sun you need power. If it's moving subjects like mountain biking in HSS mode, all the power you can get - the original AD600 manual and TTL versions can be doubled up with a twin-head adapter to give you 1200Ws. For action subjects, Hi-Sync/Tail Sync (eg Elinchrom*) as opposed to HSS has power advantages though also some drawbacks.
For power/value, the AD600 manual version perhaps offers most. The newer AD600-Pro is top of the tree and worth it IMHO for its bright modelling LED for studio (though still useless outdoors), fast recycle and (slightly) improved colour. However, if I ever get around to upgrading my system it'll be with the AD400-Pro which is lighter and cheaper, with only half a stop less power. If you can avoid direct sun, it should be enough for most things.
Another option with tremendous versatility is a couple of AD200 heads that can be clipped together in the cheap twin adapter/mount for 400Ws.
*You can also use Godox (or any other flash) in tail-sync mode though only at full power. Elinchrom is better and easier for that.
Edit: Godox are also sold under other brand names, identical products. In the UK, that's Pixapro from Essential Photo.