well the Arduino is cheaper so it would be better in the fact that after you buy it you still have enough cash to build the bot. but if it was me i would go with the axon, 1)it is a better investment for the future and 2)it has a massive community and data base of users so it would be easier if you didn't want to program.
Ad. 1 As long as you don't burn it.
Ad. 2 Googling "axon microcontroller" = 9k hits, while "arduino microcontroller" gives about 107k hits, so if the Axons user base (which is not a data base
) is massive, the Arduinos base would be what... Gigantic? in comparison.
It all comes down to a first time users choice here. Maybe a choice for life, maybe just for the spur of a moment, so I think it would be proper to start of cheap - one can allways upgrade (and one allways will, as nothing in electronics is permanently in the lead - to put it mildly).
It's just like with eg. multi-meters, scopes and other tooling!
Hands up, all of you who started off your electronics hobby with one of the better Fluke meters, a 1GHz Tektronix 'scope, a 10ns logic analyzer, Lindstrom hand tools etc.
And all of you with your hands still down (i.e. all of you): Please start giving sensible advice that fits a newbies pocket, instead of projecting your own wishes onto others budgets.