Both. I only have a Sidehack Compac Stick, a U3 and an R1 going solo as a lottery. One Miner on Jonny's pool and everything else is pointed at kano.is and has been for some time now.
The little guys will never ROI and were bought for fun, so why not take a gamble at solo!
I appreciate you and every other miner who points hash to my pool.
To OP: I mine on my own pool. Both my own hardware and rentals.
I'm split between antpool and ghash.io, I love the dependability of antpool but the gains are higher on ghash when we hit a block. I've got some hardware solo mining but it's all in places where I don't have to pay for electricity, set it and forget it kind of stuff. If my wallet ever jumps by 25BTC I'll celebrate, then promptly have a heart attack.
Of all the pools you could choose... antpool is not dependable. They don't provide mining transaction fees to miners (you only split the base block reward). They SPV mine, which has caused hard forks in the past. They are one of the worst pools for submitting empty blocks.
So many other good choices out there...