I would suggest to go for the traditional mercury based BP apparatus. Those are made in Japan and are the real deal. While digital meters have become more common, but in my humble opinion, the mercury ones are more accurate. The simple argument that I can provide is that if you repeat readings on the same digital one, it is not uncommon to get varying readings within the same setting, and I am not talking about +-1, more like +-5. However, digital ones are more convenient and easy to use for sure.