I had a 2000 40' Beaver Patriot Thunder with a without tag and thought it rode and handled wonderfully well. It had the 8 airbag and 8 shock chassis. Granted you could feel some push from trucks and heavy wind but not a "white knuckle" by any stretch.
Last year we purchased a 2002 43" Beaver Marquis with a tag. All I can say it WOW! The difference was remarkable in all aspects.
While I would not say I wouldn't go back to a coach without tag.....if it was the right coach. But I would certainly put a tag very high on the priority list. For any coach 40 or less I would probably not sacrifice the bay storage for a tag as even my 43' has a smidgen less bay storage than the 40' so that is something to take into consideration.