I use my RCF as my daily driver, after owning an ISF for 5 yrs. Boot space for me on both has been adequate, occasionally I shoehorn loads of stuff in there and yes, the split rear is handy. Agree that legroom in both is pretty similar, depends if you want 4 doors or not.
Had my 1.9 meter son in the front passenger seat and his girlfriend in the back behind him quite comfortably for several long trips.
Yes, the doors are bigger than an ISF but I’ve not had any problems getting in and out in parking spaces and I’m not svelte.
Would I rather have the ISF? No - I think driving the RCF is more of an occasion in IMHO and whilst it’s a bit bigger I think it’s a great all round car. I don’t need the seat capacity of a GSF so I’d rather have a car that’s more of an occasion to drive.
I get it serviced by Lexus Cheltenham, a bit further away for me, tho a nice drive and they do great service at a nice that compared to the other dealers in reach for me that more than compensates for a bit more petrol.