that laney gets great reviews. I only tried the other one, that tommy iommi thing, I think its the 100w version, it wasn't bad at all and not overpriced too. Has a way different sound then the marshalls though, but its whatever you prefer

If you don't play relatively big shows (lets say, 400+ people) then you'll be fine with a 50watter as long as theres a pa and you're mic'd up. If its floorshows without pa's and only a vocal system, you might want to consider the 100w, depends on your band too, if you're the only guitarist you won't have any problem at all.