Can confirm WalkTask is way quicker to get to redemption - more boxes and ads to watch.
I got to 6000 coins in about a month - redeemed that for $10 Paypal. I'm in the UK so it took a very small currency exchange fee which is why I waited to redeem $10 rather than $5, to test it out and see if it was worth it or if the fees would eat most of it! I received about £7.60 I think so not bad. I'll save up for the larger $ amounts now I know it works, already at nearly 4000 coins after nearly another month and I was ill for two of then so hadn't done as many steps as normal!
I usually aim for at least 10,000 steps a day and usually get to 11,000-12,000, not sure what the upper limit is for coins as I've done over 16,000 steps some days and the coins were still coming.
My referral code is CHMDXH.
I'm still doing Cashwalk since I'm stepping for Walktask anyway, but it is very slow by comparison!