Sigh...well...it's not going to mean you start rolling in the big bucks. There are very few internist positions for how many equine internists there are. Many internists are applying to GP jobs and being underpaid for their qualifications where the market sits.
Last year when I applied there were 16 total spots available. I'm not sure how many people ended up applying. Surgery tends to be a bit more competitive always, but medicine residencies tend to go up and down based on the market.
Just giving you numbers is hard. Dependent on location, private vs academic etc.
Equine Internships are much more the expected now, even in GP work. Most vets I know did at least one right out of vet school.