It is confusing as there are so many on the market but I think it is just personal choice I really do, as long as you are getting enough folic acid. I take Sanatogen purely because it is a brand I feel happy with.
I have wellwoman from boots.. looked at the expensive ones you can buy on line,, wrote the vit etc.. contents down on a piece of paper & then took it to boots & wellwoman has everything it needed , its cheaper as you get 90 in a box.
Not sure if Wellwoman has all the folic acid in it but have you looked at Pregnacare? It's made by the same people and I think is almost the same as Wellwoman but without the Vit A and of course with the folic acid. I got mine from Boots on a 3 for 2 offer a while back, 270 tablets for about £15 (about 9 months supply)!
My DH takes Wellman and if you top up the vit c, zinc and add some flaxseed then I think it works out similar to the MG/ZW vits, only cheaper!