Are Best + Keyword domain names still valuable?
 

I have a "best + premium keyword" domain name that I'm developing. It's in a niche that is exploding in popularity.

My question is do such names still have SEO value, or does Google (especially) and the others give "Best" domain names a spam penalization right off the bat?

I'm thinking of spending a lot of time and money (purchasing back links) on it, but wondering if I would be better off doing it for another domain name.

It is already getting a little search traffic, including Google, just from linking to it from a handful of my other sites.