The most obvious difference is they’ll sound completely different. One is a passive P/J and the other is active with dual humbuckers...
One thing I’ll say is that the difference between lower and higher end Ibanez BTBs is much more noticeable than the difference between the lower and higher end Yamaha BBs. If going the BTB route I’d personally suggest going for the best model you can afford.
Neither the BTB range nor the BB range are famed for being lightweight so I’d rule that out as a deciding factor! The 5 string BTBs have 19mm string spacing at the bridge vs 18mm for the BB, which may or may not be important to you (it isn’t to me) however, the neck profiles are very different. The 5 string BTB necks feel significantly wider & flatter along the whole length of the neck compared to the BB but that won’t be a total shock given that you’ve tried the 6 string version already.
Ultimately what drew me away from the BTB range was that the majority of the music I listen to and play was recorded on P basses and J basses, so that’s where my tastes have turned these days. Your mileage may vary!