Premier 6 is NOT recommended as a starting option. It is great programme with loads of features, but at a cost & its very hard to get to grips with.
Studio 8 tends to get the best reviews in the budget range. It has a lot of features and is easy to use.
A lot of the Studio 8 competitors are starting to catch up and might even overtake it soon.
Unless you are getting a good deal on another editing package, or it has features you require that are missing then I would recommend sticking to Studio 8. It has been out for a while and is well supported and has had the main bugs fixed. Some of the smaller software companies might not be able to offer the same support.
Just the opinion of another Premiere user still trying to learn the ins & outs.
Mark.