I have the 2 year warranty on my IS250C taken out last November @ £795 on ten monthly direct debits of £79.50. Hardly miss it !
I had cause to claim earlier this year when the nearside headlamp assembly allowed water and condensation in. I was asked for photographs of the problem and replacement was authorised immediately.
I understand the headlamp assembly is in the order of £600, so taking into account the AA membership I have had my money's worth already .
I have a further 14 months still to run on my warranty. If I decide to sell the car, it will enhance its value (secure a sale easier !) as the warranty is transferrable to a new owner for just £25.
Lexus servicing during the warranty period is mandatory I understand.