Okay...take five tomatoes each of 5 varieties. Remove skins, seeds, gel fraction. Smash them up or run through food mill separately. Place final smashed product of each variety in a clear container. wait...the clear liquid will sink to the bottom and the sauce will rise to the top. Measure the clear liquid from each variety and you will see which variety is "low moisture" and which is not. Paste tomato varieties are generally less moist (but some that are touted as "paste" really are not and contain much to much liquid and seeds...)
As I had a sun dried tomato business, I got to complete the above process for more varieties than you can imagine and the "dryness" was a BIG factor for me, with taste next and texture after that. Few seeds is also a big deal because dried tomatoes are not de-seeded...(Is that a word? Well, it is now...)
With drying or sauce, you want the most finished product you can get rather than a bucket full of seeds/skins/clear liquid to throw away and only a quarter of a bucket full of product to keep. Seedy, gel-filled, smallish slicing tomatoes are the same amount of work but you get far less rewards and they are meant to eat fresh so you lose way too much flavor and texture when they are cooked.
It just depends on what you are growing tomatoes for. Most people have some limit on available space (
) If you want to make sauce or dry tomatoes, you should maximize your space with varieties that will give you the most bang for your bucket!
But hey...each to his own. I am by far the least typical tomato grower on this forum. I grow NO tomatoes for just eating (do people really eat them? How strange...) or for salads or sandwiches. No different colors, no bizarro shapes (well...Costoluto Genovese is a little weirdly shaped) No cherry tomatoes (it should be illegal to grow them...
) No dwarfs or determinates (determinate stands for "it is pre-determined how many you will get and it is never enough on a too-small bush..."
)
And Swamper is right...climate, growing season, soil are all factors in a tomatoes final taste and some varieties just grow better in some places than others...
You know, I am really glad I don't have to make all the decisions all of the other growers on this forum do...way too complicated and way to many varieties "you just have to try"!
Got the tomatoes down to six varieties and will be winnowing down the pepper list (I only want them for ristras and wreath...no eating...) I don't eat vegetables of any kind, ever and I don't eat meat...makes it simpler!
But ask yourself...how many fresh tomatoes can you really eat? And at the beginning of the season, friends and family are happy to take extras off your hands but by the end of the season, they cross the street to avoid you and cringe when they see the large plastic bag in your hand..."Dang...how may tomatoes does she think we can eat for crimmeny sakes? I threw the last ones she gave us away when I was sure she wouldn't see them in my trash...Please God...enough is enough!"