I do 95% of my web browsing via Tor Browser and it is very tolerable, most circuits are fast enough for 1080p video (Youtube, Twitch livestreams, etc) without any buffering.

Here is a speedtest I ran just moments ago, I would hardly consider this "painfully slow": https://www.speedtest.net/result/19172283165.png

Of course this is a single tor circuit with an exit node, so speeds are slower when going directly to .onion sites, but the only real slowness comes from the latency and not throughput.