The con would be the only bagger the X-ONEi uses hangs on the deck. If you are a home owner and are looking for a smaller deck to do your suburbia lawn I would go with the Fastrak family. If you need a wider deck, and a rougher lawn or putting a couple hundred hours a year on the machine, I like the X-ONE family.
Ride them both and see how they feel. If you have hills or ditches take them both in the ditch. The answer will come to you. There are so many unknowns you need to sit in both machines.