AR-15 with 22lr conversion or dedicated 22lr platform?

[Hipster Mike]

Which is better? I suppose the build quality would be much better for the AR-15 with the 22lr conversion since most of the rifles that are dedicated that I have looked at are primarily polymer(S&W15-22 and a few others).

I want to build an AR-15 eventually anyway but I know the cost difference will be huge.

Thoughts?

[darqhelmet]

http://www.calguns.net/calgunforum/showthread.php?t=209605

http://calguns.net/calgunforum/showthread.php?t=503460

http://www.calguns.net/calgunforum/showthread.php?t=376176