1. Leather is more protective but when it comes to climate control it has its downsides. Basically with leather you need a different jacket for every type of weather condition you plan on riding in. You need one perforated one for hot weather, one solid one for cooler/cold weather, and even with vents they suck in hot weather if you can’t keep moving at a brisk pace.
2. Cordura is the industry standard but not necessarily because it’s the BEST, more that it offers a good compromise of cost, weatherproofing, and protection. Textile jackets’ strengths over leather is that they’re more comfortable (though this is a matter of personal opinion), can be made to be fully waterproof (leather is not waterproof), and one single jacket can be made to cover every single riding condition imaginable.
I own 4 jackets for varying weather conditions:
My main jacket is a Scorpion EXOwear Stinger leather jacket, which is a perforated sport-style jacket that is made to fit your body like a second skin. As I said it is perforated so it is made for riding in warm/hot weather, but because of the way perforated leather works it is impractical to use when commuting in the city because it depends on the airflow you can only get from moving at speed to keep you cool. Otherwise you’re sitting there in 90 degree weather in a heavy leather jacket and dying of heat.
My “commuter” jacket is a Speed & Strength Moment of Truth mesh jacket that I wear for commuting to and from work in warm/hot weather. Because of the nature of the way mesh jackets work, you don’t need to be moving at speed to keep cool in hot weather, so you’re fine when you’re stuck in traffic. They do generally sacrifice protection over conventional textile jackets but as long as you’re sure to get one that still has ballistic nylon textile panels in the high impact zones this shouldn’t be an issue. It did come with a waterproof liner but I never use it as it is not breathable so it is extremely uncomfortable to wear.
For days when the forecast is calling for rain I wear my soon-to-be-replaced Teknic Freestyle textile jacket. Honestly the thing sucks. I hate the way it fits and I hate the fact that the sleeve adjusters don’t keep adjustment. The only reason I even wear it at all is because it’s still a waterproof armored jacket. It’ll soon be replaced.
For cooler/colder days I wear a Scorpion EXOwear All-In leather jacket which is a solid black leather jacket that has zippered vents you can open and close (which do very little because they are small and not enough of them). This is the jacket I wear most often in the early spring/late fall because with the liner in it keeps me comfortably warm even into the 30s. I also use it as a casual wear jacket because, well, it just looks cool and you can get away with it since it’s just a plain black leather jacket.
If you’re on a budget and you can’t afford to buy multiple jackets then your best bet would probably be to buy a well-ventilated textile jacket that has a removable thermal liner of some sort, such as the Icon Contra or the Scorpion Burnout. And even if you do have money to burn on multiple jackets, if your regular riding route includes a lot of city traffic then a jacket such as this will still be a staple in your collection. It’s not a bad place to start.