I have my personal site hosted on Google App Engine too. Must say its sleek and simple. I had evaluated a lot of other (typical) options like EC2, Dropbox(S3) and even Github pages. Nothing came close to the ease and the performance that GAE gives. Benchmarking about 10 URLs on my site, returned an a.r.t of 3.5ms aggregate on GAE vs 5.6 ms on EC2.