and although both are wearable, the 5059 would be heavier due to its hinged back. For me weight is important as is size especially if you were planning to wear the watch all day long. For many, it may be irrelevant. In addition, the 3940 has the gorgeous 240 micro rotor which I feel is more attractive than the 324 semi rotor in the 5059. The 3940 is slimmer and arguably more iconic than the 5059. Also the 3940 is a much thinner watch and would fit under your personalised shirt sleeve a lot better.
2,850 Patek Philippe listings are live on the eBay market and 1721 collector listings on the WatchProSite marketplace.