[serferfish]

Unixbench is a pretty awful benchmark unless the only thing you care about is disk IO (unlikely for a typical web app). The site you linked to doesn't even have data for AWS t2 instances types, so not really a useful data point for your comparison. The site only has data for instance types listed as "previous generation instances".

[quicksilver03]

It takes a little more effort to find it but they have data for t2 instances, for example:

http://serverbear.com/166-micro-amazon-web-services

Do you know of any other benchmark that paints a different picture?

[serferfish]

Check out http://www.cloudharmony.com/benchmarks for something with more current data.