Mac and DNG

I am a Mac an LR user. I've been shooting mainly in RAW with Canon and Olympus cameras. I'm also thinking of trying Nikon. Because I've moved around a bit, I have a lot of different RAW file types. I'm thinking of converting my RAW files to DNG, but I noticed that iPhoto and OSX (Mountain Lion) is having trouble reading a DNG created by Lightroom 4.

Is this like any other RAW format, that OSX needs a patch soon to handle LR4, or is this a great symptom of the Adobe/Apple war, that OSX will not read DNG?

I don't want to do the conversion, only to find I have a format that ONLY Lightroom will understand, whereas right now, I can use my ORFs and CR2s across my OSX computers (not that I do very often, as LR does the developing, but still I don't like locking myself out of options).

Thanks for any help.