Hard comparison to make...
I have both...
SL7Led is an awesome light, lightweight, but tough, fills a whole room with bright white light and lasts for about forever on one set of Alks. The hundred plus hours claim is not an exaggeration. But, you can't use lithium AAs so, to me at least, as a standby light it has little value. Also, personally, I'd prefer the sL 7Led to have a more rounded body with more non-slip and not that bright shiny black plate - I find it a little slippy after the Surefires...
The X5T is also bright, but not as bright as I'd hoped witht the title "tactical floodlight". The wonderful thing about this light is that you still get a good number of hours of strong light and the trailing residual, but the thing is close to bullet proof and very pocketable, plus, with 2x123s I have one in each of 3 vehicles as my "changing the tire in the middle of the night" light...
When I compared these and a few SFs, I was forever impressed that the SL 7Led seemed to reach out almost sideways with light. With newish batteries, this is THE light for me to take into a dark room. Everything else I have lights up a specific part or puts a bright spot on the wall, the 7Led lights every ounce of the room - very clever reflector.
I love them both and wouldn't replace either with the other for what I use them for.
There, no help at all....sorry....
Simon