OP- In my first few miles of riding I managed to slip the rear a bit as well. I only have 5-600 miles on the bike and tires but for my style of riding I think tires do not have as much grip as I would like. I will differ from Aufit's opinion on how they feel. For me they tip in smoother than my old Ninja with Q3s, but that is an unfair apples to oranges comparison, since that bike had a different size tire, a different profile, and overall different and heavier bike.
My honest opinion is for a rider who is looking to take the tire to its absolute limits (IE a track guy or a very aggressive canyon rider, the tires suck. For average joe who is mostly commuting and doing some canyons and moderate speeds, not going all the way to the edge at knee dragging speeds, the tire will work out fine. I have dragged knee on the stock tires and they gripped fine. I also find the profile kind of weird. On my stock tires, I am no where near the edge on the rear, I have about 20mm ledt before I am at the edge of the tire. The front however is like 3-4mm from the edge. On another rider's R3 with S20 EVOs he has taken the rear all the way to the edge but the front still has quite a bit of meat left to the edge. Just a weird observation for me, as I was under the impression that it takes more to get the front to the edge than the rear.
Aufit- I switched to an S20 but I wont install them till my upcoming (first for me, YAY!) track day on the 16th of October. If the S20s suck I will hold you accountable! Kidding aside, I personally liek the S20s far mroe than any other tire I have had, since they felt amazing on my ZX6R. I like them better than Q3's which everyone around here rave about.