My background: My grandpa had a 16 foot Runabout (Sea Ray) with a 100hp outboard. My grandpa had a 16 foot aluminum with a 9HP engine. My dad has a 18 foot aluminum with a 70hp outboard. My fiance's dad has a 23 foot I/O, and an 18 foot aluminum with a 75hp outboard. Between two uncles there are 4 PWC's and a 23 foot I/O, with about 3 canoes and maybe another small fishing boat. I have a lot of experience with all of these. All of the outboards are 2 strokes.
By far, ignoring the canoes/kayaks, the easiest and cheapest has been the small aluminum with the 9HP engine. In 40 years, the only maintenance items that we've had to do on that was a new transom at about 35 years (total cost about $200). The engine has been pretty flawless too. At the end of the season, fill the last tank with STA-BIL and run it through, and then disconnect the gas tank and run it until it dies. Change the lower-unit oil at the beginning and end of each season. Probably overkill to do it twice, but we're playing on the safe side. We don't worry about the trailer since we beach-launch this one.
Our boat--the 18foot aluminum with floor--was a $1,500 boat that we immediately put about $3,000 into the engine, new floor, new trailer wires, new bearings. Don't think we could have found a better boat for the money that we had into it. Since then, we've spent about $2,500 rebuilding the lower-unit. Our engine was rode-hard and put up wet when we got it though. Otherwise put the battery on a tender the night before using it if we haven't used it in awhile, re-pack the bearings on the trailer before putting it away, and see above for the engine maintenance.
The big boats are too much of a pain IMHO. I like 20' and under. Easier to store, easier to launch, we can moor them outside, just better all around. For us.
The PWC's are great though. For $10,000 my uncle had two brand new ones. He spends about $200 a year at the end of the season having the shop check them out. They get used a LOT. For families that are mostly older kids, these are probably better than the boats. Go out for a quick 5-15 minute jaunt, come back and hand them off to someone else and go swimming or tanning or play with the dog. My other uncle has the same thing but bought his used. His have been nearly as reliable.
My dad is looking at buying a place by his brothers (on the lake) and he will get a bigger boat to go chase bigger fish, and probably 1 or 2 PWC's. But we get the use out of our boats and toys, since someone is up there most weekends. Is it cheaper than renting? We've asked ourselves this. No, it isn't. But we don't have to worry about it if we want to go out and chase the Walleyes at night or super early in the morning. And we don't have to worry about it if we decide on a whim to go up to the lake, we know the boat is there. Financially it doesn't make sense, especially in a Mustachian way. But as my grandpa has said countless times, that lake house he bought in the 70's and those boats he bought in the 70's and 90's were the very best investments he ever made, because as a family we are all so close that you cannot imagine it. Would he have had the same thing renting? I doubt it. But that has to be your call to make.