Buying a second unicycle after my first one broke- need help.

About a year ago i purchased my first unicycle on ebay for 80 dollars. I forget the make but it was a pretty good starter unicycle that had a 24" wheel. About six months ago, i really got into the sport and started to ride off road, started to learn some tricks like going up stairs, riding backwards, ect, but i finally bent and twisted the axle on my unicycle. I was wondering what would be the cheapest, toughest, best all around unicycle to buy. I want to be able to ride it on the street and do some tricks on it, but im probably going to use it for mountain unicycling most.

Secondly, i was wondering if i should get a 24" tire or a 26" tire. I was thinking about getting the 26" so that i could ride it offroad, but i read some stuff how it might not be possible to use that for other types of unicycling besides Muni. Here is the unicycle i had in mind.

Unicycle.com :: Product Information :: Nimbus 26-inch MUni Cycle with ISIS hub

I was thinking about buying this unicycle in either the 24" model or the 26", because i only wanted to spend about 300-400 dollars if i can. If possible, please let me know if you think this unicycle will be tough enough, and if i should get a 24" wheel or 26". Thanks.