I own the Mongoose Paver from wal-mart, it is a perfectly capable commuter bike. I had to order mine from the website and put it together myself. I am not a mechanically inclined person at all, yet found it failry simple to assemble myself in about 1 1/2 hours. I switched the hadlebars for flatbars I got off ebay ($5.00) got some nashbar panniers (35.00 on sale) and new pedals ($10.00) so about $160- $170 bucks for a good commuter bike. I did have to adjust the rear derailuer, I learned how on youtube and have not had a shifting problem in over 150 miles. I do have a complaint about the bike however; it is geared rather low, it is a 7 speed with a single (36 tooth?) chainring up front. My LBS said I could change it out for around $30.00 but decided against it since I mainly use the bike for short errands and trips the grocery store, my road bike gets the longer trips. So that has been my experience with the bike yours may be different but I am a satisfied with mine.

P.S. the tires are 45c, I think the website listed them as 35c