Hello,
I have been recommended by Ron and Dominik to post here and suggest my contribution to the monthly bounty contest for March.
I'm one of the developers behind
CoinsManager, a free and Open-source Portfolio. It's very easy to use, and sexy.
All you need is to add your public address, and it will automatically detect everything else: The related coin, the coin balance, and its value in your favorite cryptocurrency. Because Mastercoin shares the same address format as Bitcoin, if you try adding a Mastercoin address, it will ask you to choose the correct coin, here Bitcoin or Mastercoin.
Read more about the project
in the press releases.
The beta version is already very usable! Here is an example of a user dashboard:

We started this project a few months ago, because it was hard for us to manage our assets (how much my coins were worth), and we wanted a place to list all our public addresses, easy place to find and copy them instead of re-opening our wallets everytime. After looking up to existing online portfolio, I was very disappointed that they required us a lot of manual input (adding the transactions, or manually adding the number of coins you possess), when it could all be automatized by reading the blockchain.
We have a lot of plans for the futures, you can look into
our trello board for all the ideas/features we plan to develop (eg gamification elements). The most ambitious idea is to
host our own ledgers for all implemented coins, and build a reactive api on top of those ledgers for a blazingly fast application (basically, the server will tell clients when to update their values, there won't be anymore need for the client to query the server at regular intervals to ask for changes).
Because we like free and open-source, and do not like ads, we completely rely on donations to pay for the infrastructure and support the developers, and
contributions (cf our online doc and youtube screencasts).
A bounty from the Mastercoin foundation would be very welcome. You can send coins to
1CoinsMPAy5Mz5SVzeAmU6qNmUThiLXYv1 and give extra visibility to Mastercoin in our application.
Thank you for your interest and support!