I've got a NETGEAR N750 Dual Band 4 Port Wi-Fi Gigabit Router (WNDR4300) that I installed 2 years ago. I use Xfinity and I just checked my speed as I'm typing and my download speed was 236 Mbps. It varies by time of day, traffic, etc. I like this Xfinity speed test:
Internet Speed Test | Comcast Business.
But the best thing I did was run a dedicated cable line behind my refrigerator and installed my router and modem inside the cabinet above the refrigerator - out of site out of mind. I also have a UPS in the cabinet so the internet and WIFI still operate even in a power outage. Hole in bottom of cabinet for cables running behind the refrigerator. Most will say don't block the modem or locate inside a cabinet, but I say install it as high as you can and in the center of the house. We had a plant shelf above the refrigerator in our prior house (Gardenia). I installed a dedicated cable on the wall at the back of the plant shelf and located the UPS, modem, and WIFI on the plant shelf. It worked great. A porcelain jar and few plants to camouflage and the wife was happy.
I get great WIFI and speed in garage, on lanai, front porch, and anywhere in the house. I tried extenders and a few other things, but high in the center of the house works best.
I have a NETGEAR Nighthawk Cable Modem with Voice (CM1150) - Certified for Xfinity by Comcast Internet & Voice Plans Up to 800Mbps.