What kind of optic are your looking to get for it?
In all honesty the Mini 14 is a great rifle. It does what it is designed to do well enough. I love Mini 14's and enjoy shooting them a lot.
However, is it a good "alternative" to an AR? No. It is not as accurate or easy to "upgrade" "acessorise" or obtain/install replacement parts.
Its like asking if a Honda Civic is a good alternative to a Corvette. They are two different cars designed for different purposes. The mini 14 is a solid hunting/ranch gun. But the AR pretty much outclasses it.
Besides I thought you wanted an AR?
http://thefiringline.com/forums/showthread.php?t=459768
Get what you really want deep down. Its the only way you'll truly be happy with your purchase.