I'm not to clear on the genetics of tomato breeding. but I really like better boy tomatos for an all around salad tomato. I know if i plant better boy seeds from tomatoes I grew they won't come out as true to type correct?
What heirloom tomato is comparable to Better boy?
What are better boys parents?

Its said that the parents are Big Boy and Lemon Boy. Which are also hybrids, so there would have to be OP'ish versions owned by the seed company to produce a consistent Better Boy.

There are many OP tomatoes out there that fill the same role as Better Boy, but finding one that's just as good in all aspects would be near impossible. Such is the benefit of Hybrid Vigor.

There are "Better Boy OP" and "Big Boy OP" seed venders, but don't expect those to be just as good.

This is very informative
http://www.kdcomm.net/~tomato/index.html

I've grown a lot of heirlooms, and none had the exact taste and texture of Better Boy F1. I wonder if Italian Heirloom is similar to Better Boy: Mine last year was an oxheart cross (so not an heirloom), but it was the closest I've come to Better Boy F1, perhaps.

F2 seeds will each be genetically different from each other and from the F1. Whether they seem the same in practice is kind of random: more random for some varieies than others. Some people think the F2s are very often like the F1: I'm not one of those people, personally, with the ones I've grown.

I grew both Better Boy F1 and one F2, in 2020. They were both small, stunted plants for me. I didn't taste any of the undersized fruit, unfortunately, as the plants were smothered and I couldn't find them until after the frost. They don't like the growing conditions in my garden, I guess. However, Lemon Boy F1 and Big Boy F1 do just fine in my garden (and both grow large plants with full-sized fruit). Maybe I'll make my own unique hybrid between the two, and see what it's like. I'd rather cross Big Boy with Matina, Frittata Kitchen, Mexican Yellow, Mountain Princess, New Yorker V, Sasha's Altai, Manitoba, Sausage, Roma, Galapagos Island, Napoli, Stick, Black Cherry, Isis Candy, or Red Beauty, though.

Note: The Better Boy F1 fruits I've eaten were from my neighbor's garden. They were awesome. That's where I got my F2 seeds. The F1 seeds I had were Burpee ones from The Home Depot or Walmart.

Beginning in about 1998, I read about Big Boy, Better Boy, "Teddy Jones", Oven Schiffris, George Ball and John Peto, mostly from Carolyn Male, I planted 4 of each Better and Big Boy, we ate some, canned some, and saved seeds from some.
from 1999 on I grew and rogued, In 2000 I devoted 4800 square feet and 300 tomato plants to find a Big Pink Beefsteak out of each line.

My wife thought I had lost my mind. We ate tomatoes, canned tomatoes, sold tomatoes, and gave tomatoes away (I grew others, too). By about 2006 I had settled on two lines out of BIg Boy and 1 out of Better Boy; one of the Big Boy lines was a lovely pink globe my wife likes to fill jars with; there was a pink beefsteak out of each of the others similar to several other RL Pink beefsteaks. But I crossed them and saved seeds, growing both ovum donors' children. There was very little segregation from either line, and in 2009 I crossed again: both lines were identical in 2010, proving that John Peto actually HAD run away from Burpee with Teddy Jones to breed Better Boy.

Last year, I only grew 40 tomato plants. Mama said she's had enough.Two of them were patio plants on our deck...Mama watched like a hawk tp make certain I didn't eat all of them as they got ripe,

The story was that George Ball, of Burpees, purchased the rights to big pink beefsteak from an Ohio nursery operator; Ball offerred enough money to rebuild their greenhouses and expand operation, and used the size and flavor of the big 'steak to hopefully breed even better tomatoes. In 1939 he hired Oved Schiffris, a talented plant breeder and after the war, Burpees released Big Boy; the first commercial home gardeen hybrid. Maybe the forst hybrid tomato, period. In the 1950;s SChiffriss retired and left plant breeding to a young fellow named John Peto. I dint know the story, but is seems like Peto left on unhappy terms to start his own seed firm, Petoseeds. One of Peto's releases was Better Boy; another simple, binary hybrid like Big Boy, but with a little better disease resistance and the possibility of even higher yields...using the old Ohio greenhouse breeding stock.

Today we have "Hybrid Heirlooms"...tomatoes with specific flavors and colors designed to compete with the older ones...but they're more reliable and uniform. A couple we have tried were pretty great. There are some from a California breeder with amazing color combinations; I'll be starting two for my daughter, and probably keep some for us. But I'm guessing we will have two dozen canners, a dozen paste/plum, a couple of those "wierdos" and a couple of cherries for snacking in the garden. And a red and a yellow one on the deck in big pots.