GM has certain advantages:
(1) Their management doesn't announce with hype and miss their delivery schedules nearly as often
(2) They do know how to handle the manufacturing, sales, distribution, financing, etc...
(3) I prefer the Hummer styling, interior, and specs like HP, 0-60, crab mode, off-road chops, etc.
There are many reasons to like the truck.
I dropped my HummerEV reservation in favor the the Cybertruck for a few reasons:
(1) I didn't think their autopilot was as advances as Tesla -- and I don't like that it requires a user facing camera to operate
(2) their tech isn't as good (updating software, the UI, etc) -- GM has a habit of selling you the car and never updating it again. Tesla supports their cars after sale.
(3) Supercharger network matters -- and I think for a few years Tesla will be ahead
(4) CT has a better range (which it gets through aerodynamic and other efficiency)
(5) GM solved the range issue with brute force: they added a 200KWh battery pack to get ≈350 mile range. Tesla does it partly by efficiency (coefficient of drag). What this means is that the efficiency per mile is far worse for the Hummer. Practically, if it's 50% less effcient and the chargers are equally efficient, it means that if you go on a trip, you're going to need to charge more often (and/or for longer). I don't want charging times going from 30 minutes to 45 to get the same range.