Python 2.7 is experimental and requires migrating to the new datastore (high replication) which is a lot more expensive. So you might not want to do this if your costs are coming from datastore writes.

Also, high replication queries can return stale results unless you use ancestor queries. Ancestor queries require putting entities in groups by giving them all the same parent (which can never be changed). Basically it's a very inflexible semaphore and kind of sucks IMO.

Your suggestions in general are very good though. Thanks, I'm switching my DNS to CloudFlare now.

The HRD is the same price as the Master/Save datastore. In the old pricing regime it was more expensive, but now they are at parity.

It's true that eventual consistency of queries on the HRD can be tricky to program around. On the other hand... your data is replicated to 3+ datacenters and failed over in realtime. Pretty rad.

Ah, yes. My unusual advantage here is that SharedCount doesn't use the datastore, which I now realize is likely not the case with ThatHigh.

(In fact, when I had to migrate my app from MS to HRD, it kept failing because I didn't have any datastore entities. The workaround was to just create a single entity)

Do you see much benefit to CloudFlare swallowing half of your requests when you're already using the GAE edge cache?

As far as I can tell, the edge cache doesn't work predictably; it relies solely on standard caching at the Google infrastructure lebel. The Cloudflare caching appears to be more centralized and covers a higher percentage of hits. But, I haven't looked into the effect of relying solely on the edge cache and getting rid of Cloudflare. Can't think of any reason to try, though, since Cloudflare is free.

I checked out SharedCount, and was wondering why the front-end uses PHP.

Inertia; I initially built the API in PHP, but switched it to AppEngine when ProgrammableWeb listed it and people actually started using it. The front end uses the API though, and doesn't get enough traffic to justify worrying about scale.