I've never really analyzed it. I guess my main criterion for selecting a seed or plant is that I want to grow it. But my criteria will vary from species to species. My wife has an influence on varieties too. When she says "You WILL grow Blue Lake Pole Beans", "Yes, Dear".
Open pollinated versus hybrid isn't that important to me. I regularly save some seeds when I can but that doesn't really affect what I select to grow. Taste is important when I can distinguish a taste between varieties. That doesn't always happen. Appearance can have an effect too. Some varieties are more attractive to me than others. I'm OK with white sweet corn but corn has to be yellow for my wife.
It depends on how I'm using it. I'm OK with red cabbage in cabbage casserole but for sauerkraut I want a regular cabbage. Copenhagen is my go-to variety for that since I normally get big heads with creamy interiors. I plant a cherry tomato by the garden gate so I can grab a snack every time I go in and out. That's the only cherry I plant. The bulk of my tomatoes go into sauce so I plant a lot of Big Mama hybrid from Burpee. That's the most productive sauce tomato I've found over the season. A part of that is some standard sauce are prone to blossom end rot for me no matter what I do, Big Mama is fairly resistant. I'll grow a few for fresh eating. Jubilee seems to be a standard, it usually puts on some tomatoes even in our heat though it does slow down a lot. Early Girl is usually for fresh eating. I always try to grow a different tomato, just to grow something different. This year I'm trying Cherokee Green.
Will it be used? I grew fennel one year, we never used it so I don't grow it. I've grown elephant garlic but I'm the only one that uses it and regular garlic will work just as well for me. So I'll stick with my Silver Rose softneck for the future. I have some elephant garlic hanging I a shed drying. anyone want a few cloves to try it? Send me a message and I'll ship it in a month or so after it cures well. Offer limited to within the USA.
Will it grow here? I hardly ever get more than one meal off of spinach before it cooks in the heat, so planting it is a waste of time and space. I usually try a summer squash but the squash bugs severely limit how long it lasts so I also grow varieties resistant to squash bugs, like Tromboncini. Some varieties or species just can't take my winter or my summer so I don't grow them.
Price and convenience makes a difference. I can get seed potatoes for $0.59 a pound at the local Mom 'n Pop garden store but my variety selection is limited. To order different varieties online cost about ten times as much, often before shipping is included. That same Mom 'n Pop offers seeds of many different things with similar price reductions plus the number of seed per packet is a lot more. I may be limited on which varieties of carrots I can buy, but they have the standards and I only have to buy one packet to plant all the carrots I need. I buy most of my seed there.
Productivity covers so much ground and I've typed enough this morning. Let's just say it needs to produce. I freeze and can a lot so I need enough to freeze or can.