I’d recommend synthetics with CE armour. Waterproof, warm/cool, comfortable, and safe.
I came of at 25mph on cold tyres on a bend 12 months ago, and hadn’t even the slightest scratch on me, and not even a hint of bruising or muscle pain. My US$300 CE armoured synthetic jacket and trousers gave great protection, but was unrepairable as a result.
There is no doubt that good leather provides unsurpassable abrasive resistance. The problem is that:
1. Cheaper stuff will come apart at the seams as your body drags along the ground – leaving bare skin on deck
2. Good stuff is expensive
3. It is not truly waterproof
4. It’s heavy
With clothing, it’s always a case of ‘you pay for what you get’. My advice: If you plan to ride at high-speed frequently, spend as much as you can on synthetic stuff - almost a match for leather’s abrasive strength, truly waterproof with Gore Tex liners, and safe with CE armour. US$1500 should be enough. Should also look good too, with utility pockets, etc.
If you don’t envisage crashing over 30mph-40mph (an odd concept, I agree), then US$600 waterproof synthetics with CE armour should be enough. Then you have enough left over from the US$1500 to get a leather jacket and leather jeans with CE armour protectors stealthily hid beneath the traditional exterior for dry days. Besides, you are a Burgman rider – the permanent ‘emergency rainsuit’ is what the glove-box is for!