I rarely get out to ride in the country, but I much prefer a highway with a paved shoulder. I've written in the past about several years ago doing a one-week gig in the small town of Kenora, which had a newly built, freshly paved bypass on the TransCanada Highway. Almost every night that week I went out and did 20-40 km on the flawless and comfortable brand new asphalt. see eg
milermeter.com The pavement still looks pretty good:
In fact, I had made sure to order my Bike Friday specifically in time to have it for that trip.
The only problem was on some hills they had an extra lane for passing, and in that case they sacrificed part of the shoulder, so you'd be labouring up a long hill on a 1 m wide (or less) paved shoulder, with transport trucks passing at your left elbow. I even rode off onto the narrow, soft, outer gravel strip, if I could hear them coming fast, because I was worried about turbulence maybe sucking me into the wheels. However that wasn't great either, because in some places you were next to a drop of 10-20m into boulders or a swamp. However that only applied to a tiny portion of the route - most of it was heaven.
In town I prefer to commute mostly on residential streets, but I have no hesitation using busy streets if I need to. However I find they often have the worst pavement.
For recreation rides, since I live fairly centrally, I use a mixture of streets, and MUPs like the Don Valley, Martin Goodman and Humber trail systems.