Small pools are not for the feint of heart.
Every pool has it's good and bad times. What matters is the pool trust and support, which keeps it running. Just few examples from the past:
deepbit (my second favourite pool) is so far the only pool which had over 51%, but is now below 1Th ... just because it has no stratum (yet)
BTC Guild was close to 50% with the help of ASIC miner, but is now overrun by GHash.IO, while ASIC miner is not even on the chart
50BTC and EMC were much more than Slush at some point in time, but are now out of the chart.
Some day Slush may go out of the chart too, just because the mining became corporate business, but until then and until the pool is supported there is no reason to leave it, because of a bad day ... be it luck, DDoS or other (short, because Slush is fixing them) connectivity or stability problems.