I really enjoy mine, quiet yes but that can be effected by tyre choice, I run Goodyear Eagle F1 asymmetric on the rear (puncture at 6 in the morning leaving me with not a lot of choice and a 25 mile motorway journey in front of me) mind you they are very good tyres, still have Bridgestones on the front. Check what spec you go for either F-sport or Tukomi are the choice to make but try and get on with the Mark Levison audio if audio is important, however I find the standard audio in mine fine.
The RC300h will never beat a hot hatch or its like off the line but pop it in Sport+ when your moving and it has got a little spirit under the bonnet, it's best suited to winding A roads running in Sport or Sport+ mode just watch the right foot as it wants to push. Oh and because of the spirit when in S or S+ the fuel consumption does increase. I tend to use S+ for over taking, S for a fun drive and normal/comfort for every day driving, tried Eco and that was terrible, throttle response was slow and fuel economy was worse than normal mode. If pushed on a bend it will understeer.
As far as I'm aware they are reliable cars, except for the Lexus fuel tank filler hose recall (check it's been done) I've not had any issues. The Sonic red (code 3T5) is not any easy colour to spray so if you find one with minor paint damage it may be more expensive than you think to respray, not sure about the other colours.
Oh if you get one looking like mine you do get comments (good), I've had cyclists shout out, some others stare trying to work out what the car is then come up to me and one guy asked if he could have s*x with it!!!! Not sure if the last one is good though.