It isn't a matter of opinion, it's a matter of fact. The fact is there's a significantly bigger torque difference between the T500 and CSL-E than there is between the T500 and T300. You can't just write "IMO" before stating something that is factually incorrect, and have it be any less wrong. 0.5Nm difference between a T300 and T500 could be described as negligible, but the 1.6Nm difference between the T500 and CSL certainly isn't, especially when you consider 1.6Nm is more than a third of the T500's total torque output. Other than that, I agree with the rest of your post, that the single belt drive and brushless motor are a bigger deal than the extra torque, but the extra torque is significant in use, certainly not negligible.