This is a subject that is dear to my heart.
I've gone through 6 jackets now trying to find the perfect one. In reality though I don't think there is really such a thing as a perfect jacket for all conditions. I currently use two jackets. Heavily perforated leather for hot summer days and a 3/4 length textile adv. touring jacket for most of the rest of the time (80% of the time). I could probably get away with just the 3/4 length, four season jacket in the local climate. It is a little hot, but bearable on 30C days in heavy city stop and go traffic. You need to be moving to force air through it's vents. IMO for a temperate coastal climate like Halifax where riding below 20C is most common and riding in temps above 30C is unusual, nothing beats a good 3/4 length four season style textile jacket for general use IMO.
In my experience, don't be afraid to spend some money upfront ($~400CDN) on a adv. tour good jacket if you can afford it. It will last indefinitely, be more protective and comfortable and you'll be more satisfied with it and use it more in the long run. Problem is I've found most cheap textile jackets make sacrifices in construction (lack of venting, abrasion resistance and seam burst resistance and durability). Also cheaper jackets use polyester fill (thicker, less insulating) instead of Thinsulate in the liner, cheaper quality zippers that jam and are less water proof. Rev'It Sand jacket is currently on clearance most places. Check out Revzilla.com and avoid anything made out of polyester. Polyester only has a fraction of the abrasion resistance of say Cordura when comparing similar deniers (fabric weights/thread thickness).
Olympia AST (what I have) is fantastic (for the price point) jacket as is the Rev'It Sand. The Olympia has a built in wind/rain liner so there is no liner to lug around or put it when it rains or cools off. Just close the vents. I use my jacket as a regular (not riding) winter jacket too with the armor removed. Venting with full sleeve vents and chest vents that pin open is good enough for hottest local weather (as long as you are moving to force air in the vents, and not sitting at a traffic light) but jacket is warm enough with layers for coldest conditions as well. Mesh is better in really hot weather but even with liners is a cool in colder weather and the abrasion resistance of mesh sucks. Leather jackets have great abrasion resistance but fit too tight to layer under. 3/4 length is better than waist length for layering under because of adjustable fit with belt at waist, hip fit zippers and cinch straps on sleeves. It is also better in the rain and cooler weather with no perceptible draw backs in hot weather.
IMO can't go wrong with Klim, higher end Rev'It stuff or Olympia - they are all much better quality and better designed than AlpineStars, Bilt, Shift, Speed&Strength, Joe Rocket, Tourmaster, & FirstGear stuff.