What is typically talked about is one or two engines of the same relative size (double the cost, etc.). This is not true if you are willing/accustomed to travel at trawler speeds.
I went from a single 400hp boat to one with two 54hp engines. Instead of 8+ gallons of oil in the single engine, I now use 1.25 gallons --- times two. Went from $95 impellers to $20 impellers --- times two. Costs for ALL components and most services are much less, even with two engines.
Certainly affords plenty of engine room space with the small engines (attached pic).
Speaking of maneuvering, having the two engines roughly 13ft apart has HUGE advantages. Here is a video of us leaving a dock - moving the boat completely sideways using only the engines (rudder right, starboard engine fwd, port engine reverse). Bow thruster was only used at the very end of the video to avoid a fishing boat very close by.