cloud hosting monthly costs comparison

Most of the cloud providers charge hourly. Its easier to compare costs if we can get a monthly pricing. However the hardware they provide is difficult to compate.
The simple monthly pricing formula is [cost per hour] x running 24 hrs per day x 30 days = [cost per hour] x 720 hours a month
Here is an attempt for linux as of may 2010:

 

Amazon EC2:(Standard On-Demand Instances)
Small $0.085/hr => $61.2/month
Large $0.34/hr => $244.8/month

rackspacecloud
256MB/10GB 0.015/hr => $10.95/month
512 MB/20GB 0.30/hr => $21.90/month

opsourcecloud 
0.26/hr => $191/month
http://www.opsourcecloud.net/getstarted/pricing/

Amazon does provide the Pay only for what you use. But how does it identify our usage and what it exactly means is not clear ? Yet to figure it out. Somewhere I did read that till your app is shutdown it means the CPU is used..Would it make any sense for web app...I may be wrong..

Google App engine:
-cant write to disk.
-blacklisted set of java APIs, so few apps dont work
- cant use hibernate . So most open source apps built on hibernate wont work.
- 30 seconds HTTP response limit. So cant use streaming.
- Shutsdown app if not used for certain hours. So will give you screen deaths after first access.
- Use it only if you are ready to get tied to google ORM and big table. Also no joins..duplicate your data and...grrr..
-Then why use it ? Hmmn .. But it gives basic usage stuff for free. If you are ready to align your apps to what GAE provides and live with its limitations, then you are good to go.

Cloud is still evolving i think.
For my basic app needs, I would rather prefer to setup my own boxes and network infra to cut costs and have full control.

Reference:
http://www.raditha.com/blog/archives/cloud-hosting-making-sense-of-the-pricing.html