I wouldn't touch it with a 10 foot pole, and I've been a Mercury guy my entire life., but not 4 stroke Mercs. I still have 2 stroke Mercs I bought new in 1995 and 1998 that have over a 1000 hours on them and run perfect and look new and have never been to a dealer for anything, but they're garaged or covered and maintained!, and live the easy Florida life, but they're now obsolete so who cares? You didn't mention what size engine you are talking about either for the Yamaha or the Merc. This is my perception from 50 years of running and collecting all types outboards, 40 +/- in stock at the moment. At the risk of being internet stoned to death, it seems as though that Mercury is chasing the ultra monster, technically advanced , never done before outboard for the mega money customer to drive higher margin but are obsolete relatively quickly by limited, high priced replacement technology and parts to support new big engine sales. Yamaha, one the other hand, seems to have licked their corrosion issue wounds and focused on a more durable and simpler design further down the mid range line of engines. I purchased a new factory service manual for this SHO115 I purchased and I am impressed not only with the level of detail but also a much clearer description of revision changes between this engine and the standard F115 and how and why it works. Additionally, the dealer network for Mercury is long gone in my area and is now dominated by Yamaha and Suzuki; which is anther consideration. I'd buy the low hour Yamaha regardless of price.