This is really one of those personal preference things, there is no definitive right or wrong that covers everybody, but for me I'd much rather have one set of speakers I can translate with and listen to without fatigue than multiple sets of speakers that don't really suit me as well as the quality ones.
At my home mixing/editing desk, I originally set it up with two pairs of speakers, a pair of HR824s on the overbridge wings, and a pair of Klipsch kg0.5 home bookshelves mounted on custom wall brackets that I wanted to use as my translation check. Frankly, it didn't take very long (maybe a few months) before I realized that after the translation check on the Klipsches that I was making very few changes to the mix, and has learned how to make those small changes (in the midrange usually) by hearing the difference on the 824s, and since then the Klipsches have mostly just been hanging on the wall collecting dust. Every once in a while - maybe twice a year - I'll crank them up just to double-check to make sure my ears haven't changed tuning, but other than that, they just look neat hanging off the wall above my desk now.
In the new garage studio we have two pairs of speakers; a pair of JBL4411s powered by twin BGW amps, topped by a pair of Event 20/20p self-powered nearfields, that we run simultaneously. Yes, we can choose one or the other, but the combination of the two - when properly volume-matched - provides us with a very good-sounding and translatable result that is better then either one individually.
G.