leather is sooo far superior to the latter, IMHO..
first of all, abrasion resistance is usually not as good as you'd expect in alot of the alpine stars or relatable brand summer jackets.. take it from someone who has wrecked on loose gravel and low sided on fresh pavement in one..
suggestions:
get a bionic jacket you can wear under a regular unpadded leather jacket. a bionic jacket is usually a wide weave mesh and allows Tina of airflow while being very sturdy and yet flexible with thick pads in the shoulders elbows and ribs.. some even come with spine protectors. this way, you can always be protected and have more options as to what jacket you would like to wear, and dress appropriately. works for me most of the time.
other wise, leather is almost never as hot as you would think. unless you go for a heavy all black jacket made of thick, soft leather, you won't be sweating too bad. to me, I'd rather sweat for a minute at a stop light rather then be freezing at 70.. never thought id say it but.. leather FTW!