Premier was the top of the range so will have every option, FSport was available with a wide range of options so check the exact spec carefully.
Last week I did a 500 mile round trip (mainly motorway cruise set to 70) and averaged 43 mpg which I think is pretty impressive.
Maintenance is reasonable, 10,000 / 1-year service plus you get the Relax warranty thrown in, I have had zero issues with mine.
Be aware of the Can Bus theft issue, but there is a modification for this available from Lexus.