As far as the sbd outputs go, 95%+ of the time the output offered is XLR, which is a balanced signal. Occasionally sbds have RCA or 1/4" mono outputs, sometimes in place of the XLR output and sometimes in addition to the XLR output. I'm not familiar with the specific recorders you are mentioning but the biggest concern I'd have running a balanced signal into a deck with unbalanced inputs is whether the deck can handle the hotter feed coming from the sbd. Just make sure your feed is not overloading the deck and distorting (this typically is unrelated to how you set the record levels on the deck...i.e. you can lower your levels enough to not have the signal clipping but it can still be distorting as the feed is too hot for the deck). In this case you need to have the FOH person turn the feed down for you at the sbd.
Anyway, back to the original question, I've dealt with this before and basically I make a judgement call on how good I think the sbd feed will be vs. how good I think the aud recording will come out. Basically I give the 24bit nod to the source that I expect to be superior. This helps when you know a venue and/or the perosn mixing the sound (since the sbd feed you get will likely be the PA mix). Whichever recording will likely be the best as a stand-alone source would get the 24bit in my book, regardless if I plan to mix later.
As far as the question about long cables and/or having to position your mics in a location not near the sbd, one option if your mics will end up anywhere near the stage and assuming they have XLR output is to run your cables to the stage and hook them into the sbd snake (assuming you know the band and/or can talk them into letting you do this and they have some unused lines in the snake). This will send your feed right back to the sbd, where you can run it straight into the same deck that is receiving the sbd feed. Just a thought.