I haven't seen any real performance issues with Tier 1. It runs fine on PC, Mac and iPod Touch. Though no one has yet made a game extensive enough to really push the boundaries. Time will tell..
There seems to be some ongoing confusion about the player.
The standalone player is strictly for TESTING YOUR app. You will not be distributing the player, nor will the general public just run the player by itself. It's a development testing tool.
When you compile your app into it's bytecode form, it is linked to a COPY of the player on that machine. You can take that EXE and the media folder for your app, which contains the compiled bytecode file of your app, zip that up and distribute it to Windows users without having to do anything else.
For Mac you'll take the bytecode file and put it in an app folder on your Mac and use the XCode template project provided with AppGameKit to compile a Mac executable that contains the player that will only run your bytecode. It's the same process as the EXE on the PC, but for the Mac version. Again you can package that and distribute to Mac users without having to do anything else.
For other platforms there are similar processes to get your bytecode joined with a copy of the player. The player at that point will only run your bytecode file and no longer performs as a testing app.
For those platforms that have locked devices (typically phones) you'll have to publish through an app store.