Done some tests on battery autonomy between 3G and EDGE.
It's seems the difference has dropped significantly. I get now only 15% more autonomy by being EDGE only compared to 3G without phone calls (only emails, browsing, facebook etc ...)
If we include voice calls the difference goes to a little more than 20%.

Also in EDGE i do not experience any dropped calls, failed calls or even network path unavailable. If I go to 3G only, i experience those issues again.

There is a little memory leak (a few kb/day that never recover unless i reboot the device). Nothing nasty though.