It depends on where and when you drive.
In most cities, doing it as a full time job won't make you much money after you factor in the costs. But I recommend anybody who has a car that qualifies at least sign up and do the initial 50 to 150 rides to get the signup bonus (it can be as high as $750 depending on the city)
I rarely drive for Uber, but I am currently signed up as a driver and do it occasionally if nothing is going on a given weekend night.
I live in a smallish centralized college town and if I drive thursday, Fri, or saturday nights from around 10pm-3am I can catch all the club/bar crowd surge pricing and make $25 an hour and not spend much on gas or actually drive very many miles.
Any other nights I have tried I have barely made $10 after gas. Not worth it. As an occasional weekend/holiday side gig it's great, and I recommend it. I don't recommend it as a full-time gig. Not a bad way to make an extra $300 a month or something, but a shitty full-time option in my opinion.
But if you are gonna go full time, get the cheapest car you can that meets the requirement, and drive weekend nights, holidays, and anytime there are events that cause lots of uber requests to be made at once. Surge pricing is the only way to make any money with Uber, so you have to base your strategy around that.
On a 'drinking' holiday like St Patty's day or new years eve when lots of people use Uber, you can make like $300 with one night of driving sometimes. but on some random tuesday night you won't make shit in most places.