Currently have Spectrum as ISP, how's AT&T's DSL Internet?

AT&T is worse in my experience. I moved to Spectrum a year ago and have been pleased compared to U-verse. If you are truly asking about AT&Ts non-U-verse DSL (if they even offer that anymore) I'd imagine it's worse than U-verse.

I've heard good things about people who have Grande, where it's offered in the city. I'd imagine AT&Ts gigabit fiber offering is good too. Again, limited availability for that service too.

I just dont understand how a bustling area like frisco has limited ISPs

Its not unique to Frisco. Its the pseudo-monopoly setup for all ISPs.

I've never had issue with Uverse after buying my own router and moving toward the center of the house.

I've had both and prefer spectrum.

https://www.theverge.com/2015/4/1/8321437/maps-show-why-internet-is-more-expensive-us-europe-competition