I have the SelectTech pair that goes up to 90 - they were on big discount last year, and I splurged. I LOVE THEM! The weight dials in easily. While my dials go up in increments of five pounds, you can split your dials (say, 50/45) if you want to get an intermediate value. That plus the gloves and you're set. I like to wear gloves with them, with or without weight, for the added comfort on the handles - they balance very nicely.
On the downside, besides the price
. There are people who have posted that they can break if treated ungently, and weight room manager at a hotel I visited mentioned that careless people there had broken his fairly frequently, so that he was replacing them often. If that's a concern, you may want one of the alternate styles that is solid metal or look into whether you can get repairs locally. Also, my up-to-90s are much longer than traditional dumbbells, so I can't easily use the SelectTechs, as I might with (say). I had the traditional kind up to 30 pounds, though, and now a barbell, so that's not really a difficulty. And, it's only the deadlift and double-arm rows where this has been a problem so far. I slightly interleave them when doing chest press so as to get the center of the chest - that's not been a problem. Squats work beautifully, as do single arm rows, pullovers, etc. I am a ways off for needing to use a 'bell this big for biceps or triceps, so can't report on that
Even at that, I believe that the up-to-50s are not as big, so you might even be able to do deadlifts and such with them.