Os commerce or Zen Cart shopping cart? Need also good VPS account

Os commerce or Zen Cart shopping cart? Why?
What are your views on HostingSource.com VPS hosting solutions in the USA?
Will it be good to deal with this host? Any alternatives?

I Saved Big on Hosting - 50% off 1st month on all Servers/VPS plans.
Good service. I use the site to run my business and check e-mail on it everyday, and Hostingsource.com network performance is about as fast as any of the other services out there, but for about half the price.

QHoster.com and KVChosting.net are the best VPS providers.
I have customized servers with them almost a month and got 100% services so far.No downtime, fast support. My sites work like a charm.