The 90 is a very good machine, extremely economical. The 135 I would avoid as it has an O-290 for which parts are a problem. The 150 is great, loads of grunt and will get you in or out of anything, BUT it does use a lot of fuel.
I have been to Switzerland in my 150 and it is glorious for touring. We were two up with full camping gear, bags, camera etc. No problem even at 3500foot elevation strips in 33 degrees of heat. Super machine. I adore it.
QDM