Hi mate, i had a similar dilemma this year when our 09 IS250 was written off. After test driving the RC350F, IS350, and ISF. I ended up going the ISF, whilst the layout of the interior is the same as my old IS250, the red leather seats, carbon bits, and that amazing cluster truly makes it something special. It was miles ahead on the RC350/IS350 in driving pleasure, and that sound. Being a daily it's a bit thirsty but not as thirsty as my old RX350 in city traffic, and to be honest it's 100% worth it. If you haven't taken one for a test drive I suggest you do so.