Yes it is available from a few different sources here. I would not advise upgrading as of now because it is still a beta version. From people who have been reporting back, it seems that its a useable release but still too buggy to use for very long. Wait a few more weeks and there will be an official release. Plus, the only thing that I am waiting for is HTML email and we have to wait for BIS 2.5 anyway.
Yup listen to shooptek only thing you are missing is docs to go and being that it is the standard addition no .xls and you can't create or edit so no big wup.
I installed it yesterday. People have been reporting SMS issues where they can't send out any messages. I didn't experiance that problem, but I did have errors with a couple third party programs. JiveTalk gave me a java error when opening, and wouldn't run. I might have been able to fix it by re-installing JiveTalk, but decided to just go back to 4.3 for now.
I installed it Friday and then got rid of it on Saturday. Too many bugs and not enough change from 4.3 to make it worth it. It was twitchy, locked up, HTML didn't work. I kinda want to try it again.....but not sure.
The only issues that I can find in 4.5 as of now are:
1) the stock BB Browser doesn't like to let you click on buttons if you've selected them and then moved around on a page then come back to the button
2) sending messages seems to stall the device until the message actually sends, which is kind of annoying after a while.
I wouldn't say no issues. .45 is much more refined that .33, but it still has it's bugs. Check the other .45 threads for a list of them. Most are not very noticable, and depending on how you use your device, you may not come across some of them ie. the media player bug.