I agree- more moderate dogs (even what I would call "lighter-boned" of those moderate dogs) are usually those who do best under all-breed judges, and heavier-boned, more bulky dogs with a lot of breed "type" do best under specialty/breeder-judges. Puppies are a bit of a different story, however, since they are not mature and even those breeder-judges that like a bulkier dog can appreciate that they are still puppies and may not be filled out when they're being judged.
Do you have any photos of your new puppy?
I would enter if you're going anyhow- even just in sweeps or just in regular classes (1/day)- just for the experience. From what I've seen, you will very rarely get the great ring experience for puppies from many judges at all-breed shows (depends completely on the judge, obviously). It is well worth the entry fees just to get a gentle-handed judge who speaks kindly to a puppy, giving them a good, fun first ring experience. They don't expect a puppy to stand still, they laugh when puppies bounce around the ring, and they understand when a puppy is soft and just wants to lay down for a belly-scratch. Just make sure any judges you show under are good with puppies...
The bigger, more typey dogs often only list specialty wins, some of the more moderate dogs only list all-breed wins, and then there are the number of dogs that win in both venues and are very beautiful animals.
In spite of still being pretty new to this and with only one single show dog (and knowing that I'm extremely blessed to have ended up with the dog I have), I'm probably one of those people who only lists specialty wins because I'm personally more proud of those wins.
That is mostly because of the fantastic caliber and sheer numbers of dogs (and well-known breeders) we were competing against, and the fact that those wins were under well-known breeder judges who have devoted a lot of their lives to studying the labrador retriever inside-and-out. I was especially pleased to earn a BISS win under a breeder-judge who was a key participant in rewriting the Canadian labrador retriever breed standard recently (against some pretty steep competition).
Our points were under 6 judges- 3 all-breed and 3 breeder-judges:
1 pt- 6 mos old all-breed show (WD/BOW)
2 pt- 20 mos all-breed show (WD/BOW)
3 pt- 22 mos all-breed show (WD)
4 pt- 22 mos specialty show (WD/BOW)
2 pt- 2 yr at all-breed show under breeder-judge (WD/BOW/BOB)
4 pt- 2.5 yrs specialty show (WD/BOW)
So...all-breed dog or specialty dog? I think with many of these dogs, it is all in how they are presented on a particular day. While I feel deep-down that my dog is probably a lot more of a specialty-type dog (and does well at those shows relatively consistently, regardless of the judge...especially now that he has matured and is able to compete with the "big boys"), he also does well under all-breed judges, though with them it is very much "hit-or-miss." He is definitely not everyone's cup of tea, though I would venture to guess that there isn't a dog alive who is.
Either way, I also agree with the OP- there doesn't seem to be a group of people anywhere at a dog show that is as welcoming and friendly as most lab folks. And just think...at a specialty show, you usually get at least TWICE the number of lab folks to hang around with!

My preference for showing at specialty shows is more because I like the social aspect.