I too prefer a chain with formalwear, but mine is high quality and has never disturbed my kilt. For daywear I vote strap all the way. That having been said, as you can see by the photos, nobody is going to look at you sideways if you choose the strap for formalwear. If it's in good repair it can be just right.

Some people like to wear particularly ornate sporran chains for evening wear with embossed silver links etc... but they don't seem to be popular on this forum. I don't feel the need to run out and spend money on something like that but if I got one as a gift, I'd probably wear it.