Yea you can probably use any liqour I think the main reason is vodka doesnt really carry an aroma or overpowering flavor, even the cheap stuff. Its not like 1/4oz of rum is going to make much of a difference either.
They are both sanitary, Ive even heard people using gin and other stuff.
I have used rum on the last two batches. Havent had any problems but then again i am a noob... I am sure the great minds here on this board will lay down the law on this. And i hope i havent messed up mine either!