Blogspot vd other free subdomains?

Before I ask my question, and before everybody starts saying "free sites are crap, you don't own them, they can close your account, etc", I want to clarify that I know that. I have a paid hosting and 3 domains for sites I'm building.

But I just want to build a couple of simple sites to test some stuff I have in mind, I won't be concentrating all of my efforts in them and honestly I don't have money to buy another domain now (Paypal limited, grrr!).

Ok, my question:
As regards to SEO, will it make much of a difference whether I make those sites in Blogger, or whether I make them in Wodpress in a free hosting using one of the subdomains they provide? Can the second option potentially make it more difficult to rank, according to the domain's "reputation"?

Obviously blogger blogs are ok with Google, but I like the flexibility of Wordpress' themes and plugins.
The free hosting I have had experience with is Xtreemhost, and they seemed quite decent considering the $0 cost.

Recommendations? Thanks

EDIT: The title should say "vs", lol... too late.

I'd recommend freehostia to try out your test sites. I'd also dissent from the "get your own domain and paid host, then you own your own domain or space" line. When somebody 'buys" a domain name, they are only renting the exclusive use of it for the number of years they have paid for, they don't "own" it. Likewise, paid hosting carries with it the promise of more reliable service than the average free host, and less likelihood they will yank your space. But the actual server space is still theirs, not yours, and even paid hosts have messed around with accounts. You only really own your space when it's running off your own server.