I used to have one and found it difficult getting Joe in and out of the back. His car seat fit fine, but it buggered my back getting him in the back because of the sloping shape of the car.
Apart from that, mine didn't have run flat tyres, but I had aftermarket wheels, so they weren't manufacturer standard.
I have the 2.0 litre which was quite heavy on fuel and wasn't that fast off the mark, but perky enough.
Also, the boot is a rubbish shape so we were very limited with the pushchair - ended up with a Loola which was fine in buggy mode, but no good with the pram top as well. There's virtually no room for anything else when the buggy's in there too.
As the body of the car is made of aluminium, it dents very easily and any dings from the supermarket etc quickly make the car look knocked about and a bit shabby.
But apart from all that, I LOVED my beetle! If I had older children who could get themselves in and out of the car, and didn't need a buggy, I'd definitely wouldn't have got rid!
Hope this helps