My Dad and I had the very same debate when planning the 26 x 17 layout at his house. We went with GG simply because the MTH Scaletrax is very limited as far as what they offer in turnouts, and they sound like they can be somewhat troublesome.
We are using GG woodties prebent curves with the 37" flex for straights and Ros switches. It is taller, but can be done to look just as good with a little time. Noise is not an issue after putting the GG on homasote.
Here's a few pix of the GG/Ross track work on my switching layout.