I have many different breeds in my flock. I see no reason why welsummers couldn't be your first chickens. We have no problems with them and their eggs are a lovely terra cotta, often with speckles. They can be used in the making of olive eggers for those who intend to breed.
They also have the advantage of being an autosexing breed.
Sexing the sexlinks works only for the first generation so you have to keep making them over and over. They don't breed true. The welsummers as a breed can be sexed when hatched. The girls look like they are wearing eye shadow and have a dark line leading back from the eye. The boys have paler or broken lines and no eye shadow.
Even my olive eggers that are half welsummer can be sexed this way, so there are many advantages to this breed.
If it's the number of eggs you're after, then a sex link will give you more. However my olive eggers do lay more eggs than their welsummer mothers.