All things being equal or rather the lack of, in comparing SEER ratings for 5 ton AC units from Trane XL19i and Carrier Infinity 18. Which one has the better rating? Some of what I can find out is marketing mombo jumbo and it looks like the SEER numbrs go down with an increase in tonage. Carrier just stated a range of 15-18? Or shoud I forget about it because they are so close to each other?

Any body have an opinion as far as reliability goes for these two units. The 19i has a dual compressor and the carrier has a single two speed compressor.

Thanks for the help, I need it!