Buying a Spy Hunter, without it coming down to a comparison buy, is very hit or miss already. You're either the type of person who both "gets it" and likes the creativity behind it...or you're the type of person who doesn't get it and stubbornly refuses to.
If I had the space, I'd get one. Very unique and clever lay out.
Lethal Weapon is an entire generation and planet separated by Spy Hunter. It's not a fair comparison for either game. It wouldn't be fair for me to recommend you throw money at one over the other. Play them both and decide.