You can have "2 speed" regen of sorts using throttle off regen, which gives you light braking when you let go of the throttle and it then brakes even harder when you activate the brake switch. I've noticed the throttle off regen cuts out sooner than the regen button though, so it'll pull you up until about 15km/hr then stop braking, but then if you hit the button it'll continue to brake down to about 5km/hr.
On a related note I've also observed that while the regen braking force is only fairly mild when you throttle off but pulls up noticably harder when you hit the switch, it doesn't actually put any more current back into the battery. So alot of that potentially recoverable energy is wasted - dumped as heat into the windings. I'm sure it's done to protect the battery/BMS as most commercial batteries can't take a 2C charge, but it'd be a nice option to have for those of us with lipo. Though granted, regen is more useful for slowing down than actually recouping power.
Throttle off regen is kinda cool when you get used to it, as long as you put it on a switch so you can disable it when you want to cruise. It's like cruising around in 1st gear on an ICE bike with compression braking.
I find it particularly useful on the street when you're accelerating and braking alot, I cover a great deal of my commute without touching the mechanical brakes. And as John said you anticipate corners coming up and when to back off so it pulls you up in time. To the point where I nearly crashed the other day when I had it disabled and came into a corner fairly hot in my usual manner and let off the throttle, only to keep belting towards it. It's not like cruise control maintain the speed but when you're used to the bike instantly decelerating the second you let off, you can get into strife if you're going fast and it takes you a second to realise and then another second for your brain to over ride and reach for the brakes the 'old fashioned way'
