I have not been able to play a Hot Wheels, but I absolutely love Mustang. It is an underrated gem of a game! Also do not discount the pro...the differences moving up to prem/LE are not very substantial on this one. Very fun, fast, flowy, and unique. The code is varied, has good depth/breadth, and a good sense of humor. It is easy and fun to customize with you own music mix too.
Not a knock on HW at all...I just haven't gotten to play one yet. I hear very good things about it though, and it looks like a blast from watching streams. I think you will be happy either way!