I was at a show the other night and was getting set up and the House Sound Guy who knows me came by and asked if I wanted a patch from the board.... Since I was only running 2ch and I know the band does a good bit of audience participation and some off mic singing I opted for my gear. He looked at me like I was crazy but my recording came out great.
Same place - a month ago at a private event I was labeled "ambient mic guy" by Gusters' Sound Man... He told me that my recording would not sound good as he was mixing for radio broadcast.... In the end his mix blew chunks, I was close enough to the stage to get solid sound and when they finished with a totally off mic song I was the only one who had it recorded...
One more - same venue, a show last Dec where the band was recording and selling... I ran my gear and got a nice recording. Same band, same venue 6 months later I ran into a guy who told me that the recording that the band sold had all kinds of static and pops throughout the first disc... I gave him a copy of mine - clear...
Board recording can be a little fickle, static from output, unmiced instruments, or even having your feed be turned off by the engineer by accident... all those things turn a good night bad in an instant...
For my money when in 2ch mode I will generally go with my gear... if more ch then I will grab a board patch when available.
CQBert