I've liked Eva Purple Ball a LOT. They're a pinkish-red medium sized tomato that has zero cracking and zero bug problems and zero blossom end rot or anything else. They are just perfect tomatoes. Heirloom.

Also like the Rutgers Select a lot. They are very strong stemmed - the little seedlings look like little Marines compared to the other varieties - very sturdy. Good orange-red medium sized tomatoes with very little problems, if any. Heirloom.

Mexico Midget. Thee best cherry tomato I've ever had. Very small and red. You pop one in your mouth and you remember what tomatoes are supposed to taste like. Superb. No bug/disease problems. Heirloom.

Going to try a couple more heirlooms this year. Amish Paste (I hope I have tomatoes coming out my ears!), Arkansas Traveler and German Johnson. My family just isn't into the different colored varieties. Although I have some Snow White (white-yellowish cherry) seed, but I don't know if I'll plant any of that this year.

I believe the heirloom varieties have a higher natural acid content than hybrids.