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It depends on what you want to do with HSS.
HSS is pretty useless in conjunction with its output loss - especially when combined with high brightness levels and the requirement for substantial fill. On a bright day, you'll be hard pushed to get a balanced exposure at 4 feet using HSS and unmodified 50mm zoom.
Although not labelled with 'HSS' the T5d-R and X5d-R both perform extremely well at full output beyond regular x-sync and lose no output in the process.
Set your light ratio at full power for 1/250s f16 and the same ratio will be present with 1/8000s f2.8. On a Nikon you just need to set your camera to FP mode and use any of the Quantum transmitters.. Trio, Pilot, CoPilot, FW9T or FW10W with (or without) a D adapter providing you have an FP mode flash in your hotshoe. With an FP mode flash in your hotshoe you can augment the remote Quantum (FP/HSS) sync with on axis HSS_FP mode - adjustable - fill. The Trio is obviously better for this as it has a built in radio to make life easier, but it also works (with Nikon) with a Speedlight in the hotshoe and separate transmitter connected to a PC socket.
The X5d-R at 400WS performs the best without any noticeable banding or shutter clipping, and the most convenient setup I find, on Nikon, is a CoPilot in the hotshoe and the X5d-R as a remote. The Co-Pilot will control the remote X5d-R in TTL or switch it to Manual and operate at different output levels. Switching to Full output allows syncing at all shutterspeeds.
You'll have to try the same with Canon.