I think as a beginner you might consider adopting a more lenient attitude or it will take too long to finish projects. The more you quilt the better you get! Perhaps choose one of the projects, leave it until last and try to make it as perfect as you can and consider the others learning projects. Of course take this with a grain of salt as my quilting motto is: "It'll never be noticed on a galloping horse and that's the only kind I ride" Whatever you decide, the most important thing that you are getting enjoyment out of the quilting.
Two alternatives to your mentor are Craftsy classes. I haven't taken it but there is an online Craftsy class on Borders:
http://www.craftsy.com/class/finishi...eho-dum&_ctp=1 $20 right now. You might look at the reviews (or better yet ask on this board) and see if its for you. If you decide to stop going to your mentor and you get to the binding stage their is a great class on Finishing School: edges and binding;
http://www.craftsy.com I've taken that one and it's quite good.
I used a brother for years. If it's working for you why switch? Once you feel constrained by the machine and if money allows you can consider switching. Then you'll know what features you really need.