I looked at a similar deal, before going with a 2001 with 48,000 miles at a higher price after considering battery warranty and that I am going to be putting significant mileage on mine, and wanted some assurance that it will last me a couple years (at least until the Insight's new replacement comes out anyhow. 8) )
Some things to consider:
1) Warranty: Honda has a full warranty on the battery + IMA components for the first 150,000 miles
on the car.
If your car has less than this, and the battery or IMA otherwise dies, you will get it replaced for free at the dealer. I've heard the warranty on this replacement battery is 12,000 miles but I have not seen any Honda documentation on that point. My hunch is that they still may cover any future defect up to the same 150,000 miles of "car" mileage, but beyond that you're probably on your own.
I've seen replacement battery prices from $2,000 to $5,000 reported on this forum, depending on if its just the battery itself, or if they replace other parts of the IMA system along with it. So that is an important factor to consider since the car you are looking at is at least 50,000 over.
2) General high mileage issues: While Honda does make a very reliable car in general, ANY car with over 200,000 miles is going to have wear and tear on the suspension, wheel bearings, and other components. You should be prepared for the same sort of maintenance you would deal with on any car with this many miles.
3) Infamous water leak issue: Honda Insights have a very annoying problem where they are prone to water leaks due to gaps in the large body-colored mouldings which extend across the doors down to where the hood and fender meet.
I got surprised by this despite buying one with reasonable miles and unfortunately have had a tough time with it. This issue is beyond irritating if you live in the Pacific Northwest where it rains all the time.
Water will leak anywhere along this moulding where it does not make good contact with the body. It appears that a frequent cause of this is shoddy windshield replacement jobs. The mouldings are held on by a combination of metal clips rivited to the body which clip into a plastic tongue built into the moulding and pop-on plastic clips that slide into the grooves in the moulding.
After discovering the leak, I found out the source and mine appeared to have NONE of the pop-on clips installed, and so I ordered replacement clips from HondaPartsDeals which was a great savings from dealer prices. Unfortunately after I started installing them I found that one of the two mouldings was hermetically sealed to the body with a golf ball sized hard black silicone rubber compound and it took me 45 minutes of careful prying with various things before I could remove the moulding and unfortunately slightly cracked the windshield in the process. I then found the built-in plastic moulding tabs were also damaged by the windshield repair person when they glued it on.
Now I have bit the bullet and just ordered a complete new set of moulding / clip kits for both sides, and am going to have the windshield replaced THEN put the mouldings on myself so I can be confident its not messed up.
When looking at the car:
The water leakage is no fun to deal with so I cannot stress enough the importance of a careful visual inspection of these mouldings during the daytime. Carefully press down on the moulding all along its length and look for excessive movement and any gap between the moulding and the body. Smell the air inside to see if it smells damp, and feel the carpets in front and behind the seats for wetness.
Once you buy an Insight which does not have this problem, please be aware of this issue should you ever have the windshield replaced. The little plastic clips can break when the moulding is removed to replace the windshield, and since they often need to be special ordered its hard to put the car back together after the new windshield is installed. Probably best to order a set of spare clips and have a bag of them in the car for the installer, or just have Honda replace the windshield for you at extra cost.
Other than this one problem, I'm quite satisfied with my Insight and very glad I don't need to worry about battery replacement for awhile.
-Shawn