There was someone on here that posted that their alivio rear derailleur took like 15 seconds to shift one gear, and they thought that was normal. When you ride a bike that is, well, "entry level", you get used to things like 15 second shifts. So maybe you just don't realize the difference. Does the shift still occur in the alivio, yes, but to me that is not something I would tolerate because I have been riding bikes that shift in 1 second or less. The frustration involved with cheap bikes takes some of the fun out of the experience for me. If you like your trek 4300, good for you, keep buying them. I don't think that you would be making the same comments however if someone were to give you a $3000 bike.