[Andy_with_a_screwdriver]

I bought my 75 tourer with a set of 215/55 r16 on Union wheels. They had fairly new Autogrip P308s more of a budget (Chinese) tyre. They performed ok with no issues, until it snowed!
During last winter I bought a set of 15" Contour alloys for £40, although 2 tyres were shot, in the snowstrom I replaced them with a couple of winter Jinyu tyres 195/65 r15. These were brilliant in the snow coping with 4" with no trouble. and this is now my winter set, although the 2 rears are not winter tyres.

In the spring (April) I bought a set of 15" Comet wheels with a decent 6mm+ tread set of 4 Uniroyal rain expert tyres 195/65 r15, from a member on here (an excellent price, many thanks SteadyEddie). I used them in the spring for over 2 months with no rain! and refitted the Unions for the summer to use them up and save the uniroyals for the autumn.

In October before my trip to Paris, the Comets went back on and have been there since. They coped extremely well with recent heavy rain at all speeds.

My opinion is the 215/55 R16 gives better handling, grippier and seems more assured when driven with purpose on A roads with bends. It is also smoother on the motorway,with a load in the back.
The 195/55 r15 seem a little more twitchy at a high speed, however the higher profile of rubber makes them a bit smoother round town. Strangely these rumble more when cornering.

Winter tyres rumble more on the motorway when it isn't snowing, they are even smoother round town due to a lower pressure and softer compound. Handling at a greater speed is not so good, however they aren't designed for that!

I personally for normal summer driving would go for the wider profile as this gives a smoother ride with more grip, and the most expensive you can afford.
In winter with the increased risk of aquaplaning and snow, then a narrower profile is preferred as it performs better due to increased psi exerted on the ground for a given vehicle weight.

In the past on previous cars I have fitted wider tyres to the same wheels on Fords and Vauxhalls and improved grip and handling.