Last year I direct seeded one of my tomato plants, a Gardener's Delight heirloom cherry tomato. No cloche to protect it -- and I live in southern NY. It outperformed all of my transplanted plants by far, growing up and over the cage and sprawling on the ground besides. Plus, when the transplants were stressed by the hot and dry stretch of the summer, the direct seeded tomato did just fine. Of course, there wasn't a transplanted tomato of the same variety, so the others don't provide a true control group.
This year I not only set up my milk jug cloches, but I also surrounded each tomato seed in the composted horse manure with a circle of small stones (planted them Sunday). I figured that the stones will provide a small heat sink, not only helping to warm the soil that little bit more, but also to ward off frosts. In fact, I transplanted some peppers Wednesday and used the same method, then our temps dipped into the 20s last night. When I checked on them this morning, all of the transplanted peppers were just fine!
I'll let you know later how well the direct seeded tomatoes germinate. My thought is that so long as the temps don't dip down past the upper 20s at night, they should do fine. In fact, I'm going to try them even earlier next year -- probably around April 10 -- and see how they do.