Does a Subdomain rank suck?

Ive seen all sorts of different posts some yes some no.. So the official question.
Will a subdomain get high on google.
1. Yes - I will be using key words
2. Yes - It will be an auto blog
3. Monetising - Adsense, some sort of affiliate programs

I ask because I dont feel like buying a domain and want to use one I already have. The domain name is useless but wanted to know about google and the relevance of a sub domain..

nothing? anyone?

Google treats a subdomain as if it were a different website to the domain's website. This means the subdomain needs to perform SEO from scratch. It does not inherit from the parent domain. Remember "www." is just a subdomain that is often (but not always) the same as accessing just the domain.

Why is your domain name useless? Is the website on it banned, or is the actual name meaningless?

sometimes subdomains rank next to their domain in terms of PR.

I just had a domain with PR3 rank and my subdomain is PR2.

keywords and phrases has big deal to it too.