You were lucky to add a fan. I had considered it with mine, but I had hoped the mesh in the front would allow enough air through. Definitely going to take a look at adding fans for the next wear out.
Although the mesh was over a wide area, I knew from my Shadow cosplay that it limited visibility a little. With Shadow, it was easier to wander about on my own with the vision, but with him the brow was much higher as well. I made Excalibur Sonic look more serious, so I basically lost most of the visibility in the middle of the head, with the visor cutting the side views into pieces as well. If I needed to look at something properly I had to keep lifting the visor, otherwise I just couldn't see!
I think your costume was amazing
the spooky thing is that after SoS 2012, I had decided for 2013 I was going to make a metal sonic costume with glowing eyes and jets! But as Christmas came along, I changed to Excalibur Sonic because I had yet to see one built. I'm glad to see someone follow through with the metal sonic one XD!
Those people that go for hours in those costumes are mad! I think they must have a load of fans and one of the cool pack suits or something. They probably have a lot of stamina as well, so basically everything I don't XD! I wore a Tails cosplay in 2011 and wore that non stop for 3ish hours before having lunch and then put the head back on for another 2 or 3 for the afternoon and nearly died in it! The price of the bigger costumes.