naturally, 28's value probably gives them all a run for their money grade for grade, but that is a different discussion
my personal preference is 29...I like it MUCH better than 31...but the market seems to have determined that 31 is the "most" desirable tec comic (outside of 27, which due to price reasons, doesn't often get comparisons)...therefore, personal preference aside, I have to concede that 31 is "better" , even though to me, 29 blows it away...I assume I am in the minority on this, but that is irrelevant
If you included 28 then I think it would be
31, 29 (swapped it round for Gator), 28, 35, 33, 36, 37