I have sailed an IP 38 and have many friends who are happy with their IP boats. I don''t think it''s quite as black and white as your post implies. If you''re into performance sailing, I wouldn''t recommend an IP. However, offshore on a long reach in a good breeze, you would be in heaven. Tacking up a narrow river, you may not be happy.
There are a lot of other factors to consider though. How much time will you actually spend performance sailing? You give up a lot of things to get that performance. And how important is that performance to you? You may be willing to make the trade-off.
If performance and quality are high on your list, I would consider the new Sabre 425. I have the 452 by the same designer, Jim Taylor. It''s an awsome performer and beautiful besides.
I went to last year''s Annapolis show to buy a J46 and fell in love with the Sabre 452.
Good luck on your search.