I'm using 10.1 beta1 as a second system and it seems to work as well as 10.0, in other words it's in really fantastic shape for a beta.
I've only noticed two things wrong. The kernel has problems when it reboots for the first time after the install. The fonts in Firebird don't look as nice as in 10.0, even though I set it up the same way. If it wasn't for the font thing I'd just delete 10.0 and use the beta.
You don't have to loose a good 10.0 install to try out 10.1.
If you have the space it's fairly easy to have two or more linux systems on a hard drive. You need to have other partitions available to do it though.
Another option would be to do a backup, and just restore over 10.1 if you don't care for it. One way to do this would be to download
system rescue cd and use partimage to copy your 10.0 partition. If you don't have disk space or a dvd burner, the dar utility is a fairly easy way to split your backup into multiple cds.