Lots of good posts since mine. I will add this. I had a 1299 and wanted the latest. Ordered an Akra kit from overseas and it came with the thumbdrive. Have a good relationship with the dealer and they uploaded the Duc Perf Tune. Down the road I wanted the slide control functions that came from EVO but I had switched to the BT Moto tune. They convinced me their tune was gtg. I installed the BT Moto Stage II and can confirm I was leaving marks off the apex like a pro and not spending time doing superman off the bars. I wonder where they go the tuning from? $375 as a repeat customer as I had a left of Dimsport.
If I went with a Duc V4, I would find the cheapest race exhaust I could find and install a BT Moto tune... Lets call it $2k and done, maybe even a used exhaust. I installed BT Moto on my Honda and even with the TC set to 5 I was finding myself bucking off the seat and NOT leaving marks in a different place. BT Moto was great on my 1299, run it on my SFV4, its tolerable on the Honda but allows me to run first world gearing and tires.
My .02, until Duc came out with EVO and slide control, none of them were near Aprilia with the APRC algo's. Heck, Motorrad only figured out lean angle TC and slide control in like 2023 or something. I like the Duc and Honda chassis, but the RSV4 was still one of my favorites. Torque and great software that kept a new guy alive for two seasons. My best friend has a 23 RSV4 with the Gabro tune and tbh, for a $20k bike it is a fricken blast. Not a single problem with that bike and probably 50 track days, 5000ish track miles.