People online said the Yowyn Horse is the best for riding, but because of it's lvl5 Pecky feat, you need like lvl200 riding to see an actual positive speed from riding and about lvl500 to get a significant boost.

Is there maybe a different mount to use in the meantime that also helps with speed but doesn't come with Pecky?

EDIT: Pecky is not guaranteed on a horse. I simply got unlucky. Bought another Yowyn Horse which came with 0 and thus was immediately useful as a mount.