When looking through the Zeiss 21mm finder it's appears larger and brighter than the CV21mm finder which I own and I would think it is easily the better choice despite the significant extra cost. It's a shame you don't have a chance to check out the Zeiss and CV finder side by side, as you would see a difference but only you can decide if the added cost is really worth it.
I really wouldn't consider the Leica multi-finder. It's BIG and not optically as good at any focal length as separate brightline finders are.
If you are trying to save some money go for the CV finder, but if you have a little spare left over then the Zeiss finder is the bee's knees!