I personally love Balenciaga whites, but a work is a whole lot of bag and you would need to practice a lot more care in keeping it clean. I keep debating a white bag for that exact reason. The white bag, I feel, would get more mileage than Sahara and Rose.
I would pass on the Sahara. I think I'm in the minority of people who doesn't like Sahara, as it matches my skintone too much and it looks a wreck on me.
Rose, which rose? 04 Rose? 04 Rose is gorgeous and I would snatch that up because it's the prettiest Bal pink. If it's one of the newer pinks incorrectly identified as Rose, I'd have to see the pink to tell you. I'm not too heavily into the Petal Pink color, but I do love the Pale Magenta. I have an RH coin purse in PM and it's gorge!
With any light color bag, you need to take care of it more so as not to get it dirty/wear it out.