I did a lot of research and comparing when deciding to trade up from my Evo IX and the missus insisted that it was time I grew up a little as I gave the thumbs up to every evo driver I spotted :D .
I was after something that was value for money, had good reliability and wouldn't cost an arm and a leg to maintain. I also wanted to something that had the performance and agility like my Evo. I was reading Lexus comparos to BMW, MB, Audi, VW and Infiniti. Bang for buck nothing came close, beside Infiniti, however there was something about Infiniti's G and M models which did not seem as appealling as the IS and the Q was too far away.
Essentially it came down to a test drive and dealer customer service. I was very impressed by the customer service and the way the IS350 drove. The F-sport had subtle but menacing looks with an air of sophistication and luxury. I knew it was the one for me. The hard part for me was deciding to either wait and save for 3IS 350 F sport or get a superceded model. I decided to get a 2nd hand 2012 IS350 F-sport as I figured the extra savings could go towards hourse.
My IS is my first Lexus and definitely would not be the last.