Motion at Sea
You are looking at two very expensive, purpose-built boats. Neither of these are good boats to own as a first boat, or as a vessel upon which to learn to sail (although the Tartan would be by far the better choice if you had to chose one of these to learn to sail on).
My best advice is to start with a relatively inexpensive, responsive 22 to 28 foot, used, fin keel/spade rudder sloop. A boat like that will allow you to learn the basics quickly and help you develop an understanding of your needs and tastes in a boat. You may only own that boat for a year or two but it will greatly shorten the learning process and in the end will save you a lot of money buying or damaging the boat that you will ultimately own.
I also want to point out that there are a whole range of really wonderful boats in your size and price range. Both of these are good boats for their specific purposes, but that their purpose may not be your own and there may be, and probably are, better boats out there to suit your needs and sailing venue.