My Welsummer laid a much bigger egg than my Barnevelders do, but they're 6-7lb and my Welly was 9lb, so that may be the difference (I'm not sure if the 9lb is normal or not haha, but she was a big gal!) My Welsummers eggs and my Barnes eggs are around the same shade of brown (welsummer had speckles)
I've owned 1 Welsummer and 2 Barnevelders so my experience is fairly limited, but our Barnes have been fairly nice, not super super friendly despite being hand raised. Gorgeous lacing pattern however. Welsummer have more of a standard chicken color (partridge i believe) but I honestly love the look since everything else we have is different! She was very friendly (she was also hand raised) and wasn't a bully any more than any other chicken was.