You've been pretty lucky, it seems. Maybe you'll be pretty unlucky for a while after this.
The point of being in a pool is to reduce variance; instead of randomly receiving 50 BTC at virtually unpredictable times, you receive smaller amounts at more predictable times. If you don't mind the variance, then by all means mine solo.
This exactly, I would suggest switching now.. but of course in the "long run" you will always come out making more because you aren't relying on a server to be up 24/7 and you aren't paying any fees.
So you get less downtime and more BTC.. hmm..