I voted both as Galactica has without a doubt been comercially beneficial to Alton Towers, I've heard several people say, "let's go to Alton Towers to try that new virtual reality coaster". It does have an appeal to it and in that regard it has been a good investment. I also think that the area surrounding Galactica has had some good work done to it. The Rollercoaster Restaurant is a solid investment and as others have pointed out the soundtrack and portal are very welcome components!
However on the flip side, I do think that the virtual reality component of Galactica either has a limited lifespan, or will require regular re-investment to keep it up to the latest advances in technology. We have seen at the likes of IAAPA that virtual reality is going to play an increasingly important role in the amusement park industry so I think that there can't be much harm in giving it a try for a few seasons at least. However, I do think that the money spent on Galactica could have been better spent elsewhere, for example on a new flat ride to replace Ripsaw or Submission. I know as enthusiasts we do bang on about flat rides a lot but I think we have a valid point. A park needs more thrill attractions that just rollercoasters unless it has a ridiculous number of them (Cedar Point etc).
Overall, I have mixed feelings on Galactica but towards the end of the season I began to encounter more and more problems with the virtual reality which made me question the longevity of the investment. So, I think it has been a much needed draw for Alton Towers in 2016 and will continue to be in 2017, but with SW8 scheduled to open in 2018 I think that Galactica could soon be overshadowed and the VR content removed or changed altogether.
Personally I feel as though the Smiler has brought more people than Galactica
The Smiler did cost over £15 million more