Among the three I like him the most. He has great mobility and decent damage too. His ulti is great against multiple heroes too. You can spam 1st skill too (although they changed it, before it has no cooldown)
Martis, ahh he couldve been my number 1 but devs couldnt make up their minds what to do with him specially his 1st skill. But, dont get me wrong he is still pretty good though.
Aldous... hmmm his damage is good specially when you want to kill those squishy heroes ASAP but you need stacks before you can do decent damage and getting to the backline is no easy task specially in teamfights. For me aldous is great finding those heroes who likes to roam solo (specially in classic mode where there lots of solo gamers) in the map or those sneaking towers.
But this is just my list. :)) I hope others will provide us more in-depth analysis regarding these three heroes.
I would recommend Martis coz he is the meta now. You can buy thamuz if you wanna try new hero, also he's getting a buff soon. Aldous for late game monster. GG