I'm assuming you're asking because you're equally fond of cherries and plums. I only just planted my two sweet cherry trees last fall and I have a couple of plum trees. But I'll share what I know....
First of all, you get better price and SELECTION on fruit trees if you plan on planting them bare root while they are dormant -- that's to say -- you place your order and they ship to you very early in Spring (in early March in zone 6b) or late Autumn (I think early November). You do want to order early because they might run out or only have mediocre ones left (I think that's when they put them up for sale
) I've purchased from Stark Bros and Miller Nurseries but there are others excellent nurseries as well. If you buy potted trees, they can generally be planted later in the Spring before the hot/dry season and earlier in the Fall (My purchases from Edible Landscaping -- another good source -- came mid Sept.) My criteria for choosing mail order/on-line source is a nursery that is relatively close to my geographical location as well as climate. Remember that your plant will be wrapped up and in transit for a number of days, as much as a week or more. I like to keep shipping stress to a week at most.
Most fruit trees are grafted onto a root stock. The type of root stock determines the ultimate size of the tree and the kind of soil they can grow in. Root stock can also affect disease and pest resistance. I choose a disease resistant variety of any fruit tree so I won't have to spray with chemicals. I'll be using a clay suspension product called Surround this year.
Now, are you thinking eat them fresh or are you thinking cherry pies and plum jelly/butter, etc.? Fresh eating cherries are sweet cherries. They prefer well drained soil and you usually need two different kinds to cross pollinate each other (Few self-pollinating exceptions, also 2- or 3- in-one grafted trees) Pie cherries can handle somewhat more clay soil and also does not need as much sun as sweet cherries. They are self-pollinating and you only need one, though two will produce more.
Golden sweet cherries are supposed to be less attractive to birds, but you'll need birdnetting regardless. Dwarf tree would be easier to cover/maintain -- you need to prune both cherry and plum trees frequently (at least once a year). Also remember that you'll eventually need a ladder to harvest from full sized trees. If you have the room, standard trees would produce more and you *might* be able to share with the birds, but I don't know this from experience.
Plum trees usually come in European and Japanese varieties. There is an American native Beach Plum as well but I'm supposing that's not what you're thinking of. There are also crossed variety between Plum and Apricot called Pluots and Aprums. European plums are supposed to be able to handle clay soil. My trees certainly are not showing any sign of stress. You need two European or two Japanese varieties to cross pollinate. Again, 2- or 3-in-one grafted trees are available.
For both cherries and plums, make sure the varieties you want are suitable for cross pollinating each other.
Going back to pruning, also look into "espalier".
This is probably more info than you were looking for, but I hope it'll be helpful in your selection.
