Hi - I have a City elite and so far it has been great. To be honest the two you are considering are very similar.

When I did my research the main differences were the city elite's rear wheel base is 1" narrower than the mountain buggy and there is no toddler seat attachment available for the mountain buggy whereas there is for the city Elite. Even though the wheel base is smaller than the mountain buggy - it is still v. wide. I find I get 'trapped' occasionally. It doesn't bother me though.

Also - I spoke to the aust distributor for baby jogger and they told me the city elite was the only 3 wheel pram on the market that you can actually jog with - although not very far - only 3 -5 km and on a smooth pathway. I find it a bit rough occasionally but I wonder how rough other prams would be - probably equally as bumpy!

I like mine though!