It's amazing what harmonizers can do now. As has been noted, it opens up a huge amount of songs that, at least for me, don't work well for a solo singer. The only thing to be a little cautious about is overuse of them. It's easy to be so impressed with "your" sound that you want to use harmonies on everything and then it becomes overdone. Some discretion helps keep the "wow" factor. I saw a guy at a winery outside of Austin a few months ago who used one in exactly the same way on every song and listeners went from thinking it was really neat for the first couple of songs to saying he just sounds the same every time.
So it's best to be judicious. For example, on one song I perform I add a single harmony voice to only one line in the entire song. Other songs I don't add harmony at all and on a couple of others I use the full capability of my Digitech, two harmony voices plus a lot of reverb/chorus/delay. But regardless of how I actually use it as far as harmonies, I always use it as the "mixer" for the voice and guitar, even if none of the harmonizer's other capabilities are engaged for a particular song.
The first song I ever did with it in public was the Bee Gees' "New York Mining Disaster 1941" and people were just blown away - several people came up afterward and jokingly asked how I managed to get Robin and Maurice into that little box.
Re the Porchboard…yeah, I think you nailed it…a background pulse rather than a pounding bass ends up almost being automatic. I had been approaching it more like a real kick drum with some typical rock-type hits and I just couldn't do that and play/sing.
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