Interesting discussion here. I bought my 36er about 3 1/2 months ago, end of April, and have been commuting to work 16km (10 mi) x 2 about 2 to 4 days/week. I’ve only ridden a 29er a few minutes and transitioned from a 24" MUni. (see Transitioning to 36" from 24")
After getting used to the 36er with 150s I changed to 127s and do quite well. Pretty quickly I was making it up the not so steep climbs and have progressively gotten better with climbing (my balance actually). In the one direction I’ve got 2 short climbs of around 10% and in the other direction I’ve got 2 climbs, one relatively long and one really steep around maybe 15-20% or so (i.e. about half of cyclists push their bikes). I’ve been riding all but the really steep one every time for maybe the last month or so. And, just yesterday I finally made it up the really steep climb, kind of with a big weight shifting from one pedal to the other sort of like standing on a bicycle. So I think I could even go with shorter cranks. I have bad days but over time continue to get better: fewer UPDs, faster speeds, making it up more hills (and down always now).
As to the comments about time/speed I agree and disagree: on the one hand I am obviously faster on a bike, so in general I ride the 36 for the experience, challenge, fun and for the health of my back (unicycling has completely eliminated the minor disc problems I have had for about 10 years now). On the other hand I prefer to keep my commute under an hour and would also like to be able to shave off 5-10 minutes by going fast if I decide I want to (presently I sometimes have bad days where I simply cannot make it in under 1 hour). Plus, I have to pick up my daughter a few days a week from the day care and I often decide I have to take the bike to ensure that I will make it in time, so I would like to be faster on the unicylce and/or at least have the capability to speed up if need be, so that I can take the unicycle more often. On the bike I know that I can push hard and make it fast. Presently I cannot do this on the unicycle: on a good day I can’t get under 50 minutes and on a bad day I cannot make it in under an hour no matter how hard I try.
Time on the bike compared to the 36er:
Booking it on my speed bike and crusing over 30km/h I can make it in 32-35 minutes and going at a for me normal quick pace with cruising speed 28-30km/h I need 35-38 minutes. On the 36er I take between 50 and 70 minutes, so roughly 20 minutes longer or 40-100% longer than on the bike.
Speed: These days 16km/h (10mph) is easy, 18km/h is my quick sustainable cruising pace and on a day like today I was sustaining between 19km/h and 21km/h for almost all open parts of the whole ride (my max speeds per ride are usually between 20kmh and 23km/h with 24km/h being my believable max max and maybe 25km/h but not so reliably measured). This makes my averages including the climbs and lights and having to slow down something between 13km/h and 16.5km/h (on the bike my total average is usually a little over 24km/h with a cruising speed of 30km/h).
Note that when I was considering buying the 36er I was optimistically hoping to be able to make the commute in 50 minutes after a long while and a lot of training (see Transitioning to 36" from 24"). Thus, I think my estimate was pretty good, as I have now made it in 50 minutes a few times (even though usually I don’t), and it seems reasonable that in a year I should be able to consistently make 50 minutes if I want to.
The 36er is slower but more fun and better training, especially as all-body workout as the bike only trains the legs and lungs, but the unicycle gets the back, stomach, shoulders, etc.