Personal preference. The upside of a bidet is that you'll use less paper and more water which is better for your black tank and the environment. The downside is that it will use more water which will drain your FW and fill your black quicker. Not an issue with FHU. You can always shut it off when boondocking. I am sure any aftermarket, bolt on model will work.
its almost a difficult decision which way to go eh. put a bigger fresh tank to compensate, black is easier to clean out.. mind you the extra water used in flushing toilet paper down, might be what a bidet will use anyways so it might be a wash..
