IP vs Tartan-other options
I think that there are a very wide range of boats that would fit that bill within your generous budget. The IP and the Tartan represent nearly extreme ends of that spectrum. Towards the IP end of the spectrum (robust, comfort oriented) would be boats like Shannon 42/43, Mason 44, Brewer 44, Brewer 12.8 Pacfic Seacraft, Northwind 43, Outbound 44, Taswell 43/44, Wauquez 40 or 43, Valiant 42, Cabo Rico 400, and Halberg Rassey 39 or 42, all of which should offer better sailing performance and ease of handling with similar quality construction.
On the performance end of things, there would be the Tartan 4100/ 402, Dehler 41 DS, Hanse 411, Sabre 402 or 426, or J-46, J-42, all of which offer very good performance, high quality construction and which are also fully intended to be offshore capable. You also might consider upgrading a boat like a J-44 which can be purchased for substanially less than the boats that you are considering but which would make and excellent distance cruiser. (A least one has circumnavigated and I understand that that boat is now in the Pacific nearly half way around again.)
I still think that you need to study up some more to understand what it is that you personally want out of a boat.