The seating position is comfortable and can be adjusted widely (including good lumbar support) for different drivers. Note that we have the SEL version with electrically adjustable seats. I've driven multiple hours in the seats with no issues. The view out the front sides and rear are good for a modern large hatchback except for the thick A pillars which obscure a little of the road in turns.
When poodling around town and keeping things light with the the throttle, the engine switchover is surprisingly unobtrusive. The ride is generally quiet excpet over rough or textured surfaces. There is a degree of wind noise at highway speeds, but it isn't at an objectionable level and is expected for a tallish car of this shape. The only time it gets really loud is when accelerating hard at which point the engine noise really lets itself be known. At least you get a reasonable amount of pickup along with the noise.
Please note that this is relative to competitive hybrids of which we tested the Prius V. Compared to the V, our C-Max has much firmer handling while maintaining a good degree of ride comfort. I think the best way I can put it is that the C-Max handles curves and turns like a decent, non-hybrid front wheel drive sedan, so confidently enough, though it's no go-cart wannabe.
We've hauled some improbably large stuff in the back with the rear seats folded flat which leaves a nice level load floor. Just picked up an armchair and ottoman and stuffed both in with room to spare. It's hauled over a hundred pounds of scrap metal and lumber without issue. The largest load it's taken was a 7.2 cubic foot chest freezer which just squeeked in. The above only applies to the regular hybrid version of the C-Max. The storage space is seriously impinged in the plug-in Energi version which sticks a larger battery into the trunk space which both reduces storage with the rear seats up and leaves you with an awkward and uneven load floor when the seats are folded down. this was one of the main reasons we went with the regular hybrid.
With some care, it is not too hard to surpass the revised EPA estimates of 44 city / 39 highway. It particulary shines in city and suburban driving where you can crest 50 mpg on some short trips. In mixed driving, we match the EPA estimate of 40 MPG without paying much attention. While not as great as the Prius, this efficiency was certainly a step up for us and the difference in fuel costs over a year between the C-Max and Prius was not worth the shortcomings we found in the Prius (particularly poor handling and uncomfortable seats).