I own both and I race both..... so I can say without a doubt.....
The losi is more fragile
The losi is WAY heavier in stock trim
The losi is fast, but the mission is easier to control fast
Out of the box the Losi can be competetive, but only if our skills are up to it, The Mission..... Build it, race it, win with it....
I race the Losi on unprepared asphalt tracks where I have a chance to get rocks in the belts
BUT over-all I think the losi and Mission feel a good bit alike.... that is the reason I kept the Losi instead of my FT TC3......