GM has some of the best cars on the market and the reliability great!
You just gotta go for their fully electric models. From my personal experience and others. Spark EV and Bolt are freaking tanks. Volt is meh that hybrid drivetrain is no bueno I'm hearing
Ford has an issue with stop safely now on the ford focus electric, it is on every year as such I worry about the Mach-e cooling.
Fiat is Fiat but much better than gas and bosch did have an issue with the engine but it was fixed in later models. Fiat just uses freon for the cooling the battery, so you gotta always make sure the A/C condenser works is probably the weak point now.
Nissan has had battery issues so I wouldn't trust their cooling if ford hasn't figured it out
Mercedes all electric B class and BMW i3 rex also had issues (people abusing that motorcycle engine vs JUST emergencies. Luckily the rex engine is a 2 stroke motor, any BMW motorcycle mechanic can fix it easy and cheaply.
Mercedes was I think electrical grimalis as always.
The Toyota Rav4 (gen 2) with the tesla batteries are junk.
Honda had a fit that was a lease only so noone knows how reliable because second hand market doesn't exist. Which is when issues come up, jeeps work for 5-8 years or until you sell the damn thing the dad said XD
If you ask me GM is great for pure electric and are the only ones who did it right the first time and beyond (I'm looking at you electric prizm).