We have an O/B on our 28
PO (previous owner) pulled out OMC Saildrive that was giving him fits, and glassed over the hole in the hull. We got it with a Yamaha 9.9 4-stroke on an overwhelmed Garelick motor mount (not made for a 4-stroke) and is now clamped to a new and very significant motor mount. Advantages:1. easy to take to mechanic in the off-season2. delivers 6.5 knots boat speed3. quiet inside boat while under power4. seems to sip gas, but we have no experience with an inboard engine, so what do I know5. rigged up for electric start and control cables to pedestal control levers with little trouble6. much more accessible for DIY servicing7. zero drag when raised out of the water8. easy to clear when they get fouled9. one less hole in your hull10. not as ugly as you would think (but what do I care anyway)Disadvantages:1. loud when you are in the cockpit2. either heavy to lift (motor mount springs too old/light)or hard to push down (too heavy duty springs in lift) into the water, but can be cumbersome and at an awkward angle3. in rough seas (even in our freshwater lake on occassion), the bow-to-stern rock of the boat can both pull the prop out of the water and then get very close to submerging it; I'm fairly sure that when you are in that kind of weather, you want your prop to have something other than intermitent contact with the water4. if the motor quits and weather is a bit rough, do you really want to be leaning WAAAAY out over the transom?5. they can fall off of a boat if something breaks on the mount (then again, so can an inboard's prop, but I think a new outboard is going to be more expensive)6. will NEVER charge your batteries the way a good inboard with a decent alternator can7. not a traditionally yachty look (read: ugly)8. did I mention they are loud?I really think it depends on the environment in which you sail. Big ocean swells could really put the hurt on an outboard and weaken the bracket/transom. That said, an inboard is probably overkill on an inland freshwater lakes. We use ours to get in and out of the slip and when wind dies and it's getting dark. That's it.Honestly, there are days I would like to chunk ours and install an inboard/saildrive, and there are boats at our marina with owners wishing the same about their inboards. Look at what you need, what environment you are going to be operating under, and really examine what is important to you. Let's see what others think. Should be a good post for the group.p.s. As to your question about boat balance, weight shift, etc., I have no clue.