They do fine - just mushy when thawed. You'll find this often discussed in detail over on the Harvest forum here since its focus is preservation - canning, freezing, dehydrating, etc.

Dave

I have an abundance, YES, an abundance of paste tomatoes this year. I am very happy.
I just let my fruits color up on the dining room table, then I put them into them freezer bags and into the freezer they go.
When I need some tomato sauce, I just let them thaw a couple hours, then I put them in boiling water for a minute, take them out, let them cool for 10 minutes, peel off the skin and into the sauce cooking pot they go.
You could make the sauce and freeze it if you wanted, as an alternative. That's probably better as you can get the exact amount of sauce you're needing for the meal you're making.

I don't bother thawing frozen tomatoes. I hold them under running water to slip off the skins ... then chop up the tomatoes to toss in whatever I'm cooking. My hands get pretty cold before I'm done. ;)

I clean up the bad spots, cut into pieces, and shove them in freezer bags. They stay good all year and I drop the whole frozen chunk into soup or chili. I don't mess with skins.

If you are using the defrosted tomato for sauce, it will work really well. But as Dave said, the texture will be very mushy so it won't be good in things like a chunky salsa. I generally peel and half the tomatoes, take the seeds out and drain them well before I freeze them in gallon size freezer bags.

I've also frozen them whole with skin on before. The skin comes right off but taking seeds out is much harder at that point. Plus my hands get very cold.