I use a double sided metal dog comb for routine grooming. Brushes don't really do much, in my experience. You need to get down to the base of the fur. Brushes tend to skim the top layer, and with tiny bunnies like Nethies, brushes tend to be too big to do all the fiddly bits anyway.
I find short haired furries are the most difficult to deal with when they are moulting. Running damp fingers (or wear rubber gloves) through the fur in the wrong direction tends to remove loose hair, especially if there's a bit of wind to help blow it out as well.
I think all furries do need grooming. Rabbits will ingest fur from grooming themselves and their companions. If they ingest a lot, it can cause digestive blockages. Doing a proper groom weekly helps to prevent this, and you get to know the condition of your rabbits better, and spot when things are not quite right. Handling them for grooming also helps when they have to be handled by others eg at the vet.