My LS is a 2004 and, unless things have changed in between these years, no Navigation means you have the most basic model. The car will be boring in every sense of the word - both in a good and bad way, as others have posted. No real maintenance issues, no little things you have to figure out (i.e., when you first sit inside, you probably can already work everything), but will never be mistaken for a sports car. Make sure that you have tires that "fit" the car - mine came with "performance" tires (purchased CPO last year) that transmit way more noise into the cabin that I'd like, but what can you do? My tires are Goodyear ResponseEdge with Kevlar - supposedly quiet, but I wouldn't pitch them as such.
One major plus (to me) about the basic model is that it has parking sensors rather than a backup camera. This is definitely a personal preference, but I have found the sensors to be more useful than the camera, although I couldn't tell you why.
All in all, I'm pretty agnostic about my ride, so I'll just highlight a few of my pro's and con's after a year of owning a LS430 - comments with the word "surprising" are relative as our expectations may differ:
Pros:
- Very good drive train - the engine is smooth, powerful, and well matched to the transmission.
- Everything "just works"
- Surprisingly small turning radius
- Blocks out most outside noise very well
- Interior is incredibly comfortable and well put together
Cons:
- A surprising amount of noise can travel through the bottom of the vehicle - especially through the tires. This might be alleviated some with different tires - maybe someone else can comment.
- Suspension is not as great as some reviewers make it seem. The times I get that "driving on glass" feeling are few and far between; again, since I'm in the minority, this might be due to the tires
- Suspension handles big bumps amazingly well, and small bumps surprisingly poorly.
- The cooled seats don't really work all that well - if your backside is hot, the cooled seats will only make them slightly less hot.
Huge Con (for me)
- Lexus CPO warranty is non-transferrable. This was not pointed out to me before I bought the car (yes, it was in writing, but I didn't catch it until a couple days later). Since you plan on keeping your vehicle for a while and you haven't mentioned CPO at all, I'm guessing it's not an issue for you.