Do I need a 301?

What's the best way to retain rankings?

[hundredly]

We're slightly changing the domain name of our ecommerce store. What is the best way to keep the existing inbound links and rankings that the store already has?

I was considering to setup a new hosting account for the new store name (storeB), and then have every page on the old store (storeA) point to the corresponding page on the new store (storeB) using a 301 redirect.

Though - I think we could handle the change even more simply, just by setting up the old store name (storeA) as an alias for the new store (storeB).

My initial thoughts were that the 301 solution is more correct - though, after hearing how unreliable 301 redirects have been with Google lately, I'm just not sure.

Also - another advantage of using the alias is that we don't need to pay for a separate hosting account.

What's the best way to do this, while keeping our rankings? Would this alias approach have any disadvantages?

thanks!