Its basically a Corolla with a 2.5 engine. They are very reliable but I would check out common complaints on repair bulletins and online websites and look out for them when purchasing. Remember to bring it to a mechanic before buying and let him check it out.

https://repairpal.com/2007-lexus-is250/problems

https://www.carcomplaints.com/Lexus/IS_250/

But just to note that the mid->late 2000's Lexus/Toyota cars had a huge plummet in quality when it comes to mechanically and cosmetically. Buy one with lower mileage that was taken care of. Apparently the 2006-2007 had more issues than the others. Some don't trust it but still, a survey of millions of vehicles compiled by consumer reports shows that the IS350 was more reliable than the IS250.

If you follow my sigy, yea, great first car imo.