The new Sturmey 3-speeds are very nice, and very cheap. Not the same quality as a Shimano, but not the same price, either. You'd do fine with either one of those (Sturmey or Shimano) though Sturmey has more options to choose from.
As for the 7-8 speed IGH option, everyone seems to have glowing reviews of the Shimano Alfine ones, I haven't seen anyone comment on the SRam IGH units. I myself have a Sturmey 8-speed hub, which I love and got for a very good price, but the gearing requires a very small chainring. Most hubs have the middle gear as 1:1 but the Sturmey has first as 1:1.
Since Shimano came out with the Alfine hubs, the older Nexus hubs have gone way down in price... a good 3-speed will cost you around $70, and the Nexus 8 I've seen listed for $180, but it gives you the full range of gears. I paid $130 for my Sturmey 8-speed, and it came with everything.
So look at your budget, you can get many good choices under $200, and if you think a 3-speed will get the job done, less than $100. If the bike is very heavy and the hills are pretty steep, it wouldn't hurt to go with an 8-speed.
I'm sure some others with more experience with the different hubs can chime in, too.