There isnt really a 'best' formula, they all have the required nutrients for baby, so its just going to depend on what your LO gets on with. Unfortunately the only way to know that is to feed your LO and see how it goes. Sorry its not much help.
If youre really worried about the sma then choose a different one, apart from losing a little money theres no reason you cant choose a milk you feel more comfortable using. But on the other hand, there might not be any problems with the SMA.
We tried Hipp at one point because we'd heard only good things (and thought it might help with some issues LO was having at the time), but our LO didnt get on with it at all, so we went back to Aptamil, but obviously a huge amount of babies get on really well with it. And we started off with cow & gate in the very beginning, and thats made by the same people as Aptamil and is supposed to be pretty much identical - but again LO just didnt get on with it. So its just very individual.
Try not to worry about it, whichever brand you go with will give your LO what they need, and although not ideal, you can switch at a later date if you find your LO isnt getting on with it at all. Not to be done lightly but better than your LO not feeling well because of it.