Splendid,
For me it's the pride and preservation of my engine. Down the track if you ever want to sell your engine, the appearance is going to look a whole lot better than an engine cover that has been exposed to the elements. If you intend to sell you engine in the future I think it’s worth the $180 investment.
If you concerned about the cost of a genuine cover, a motor trimmer will be able to make you one for around half the cost. Also I noticed some large retail outlets that sell "Boating, Camping and Fishing" items also have a cheaper alternative to a genuine cover.
Cheers, Jado