Well, if stereo makes no difference... No, sorry, I can't help myself! Stereo makes a HUGE difference
Primarily, for me, it's about the size of the things. Put up a couple of Podium's in the sweet spot on the corners, and you are almost obscured, compared to the Mackie's... I wouldn't be at all surprised if the Podium's get louder and fuller, but getting the Mackie's in close does the job without taking up any more space onstage than I would without them. Not so the Podium's. The Mackie's are DESIGNED to go on a mike stand, it would be easy if I wanted to make an attachment and mount them on the stand itself, those Podium's are too big for that, so you've got to use speaker stands (much larger).
I like the easy to get to front panel controls, all the little extras (phantom, pass through jacks, RCA, 1/4"/XLR combo jacks, easy EQ access) and the fact that, should it die, my local dealer takes care of it and I get a floor unit to cover me while my repair is sorted out (haven't needed that yet!). I'm afraid that, until the Podium's are widely available locally, I won't touch them, but primarily, it's about size.
Having the controls on the front (where I can get to them while I play) having three band EQ, having four different sets of inputs, including stereo RCA, having a detachable cord (what's with THAT?) and having a frequency response DESIGNED to roll off the low end all count in the Mackie's favor, IMO.
But I wouldn't discourage you from trying the Podium's if you want to just try them out. On paper, they look fine. Crank them to the max, though, to see what they can and can't do...
http://www.mackie.com/products/srm150/ http://www.podiumproaudio.com/podiumproaudioproduct/poweredspeakers.html