I have the
Garmin 4210 with the 18 inch HD
radar. It is new this season and all I can say is that it is awesome. Some complain that the
Garmin radars dont have the individual tuning controls that other or older
radars do and they are right. But I have to say that isnt a problem because I dont need them. The HD is so sharp and so accurate that I really have no urge to tune it at all. This is after using it in 20 knot winds and in major rain storms. Once you see the HD you will never go back. I dont know what a 24 would give that an 18 doesnt - probably better range, sharper definition, etc. but the 18 is already very very good.