I've been accumulating btc ever since the huge dump in December, now I'm switching to alt-coins. I strongly believe that alt-coins will experience a mini bull run vs btc in the following months.
I believe this as well, however I don't think the time to switch to alts is just yet. BTC is still rising fast, and whilst some alts are also rising, they are not all rising as fast as BTC. So I would say BTC remains the safer bet for the short-term, and then once it starts to slow down it would be the time to move to alts... but that might just be me being a bit risk-averse
If you are already in this market before you should have known better than switching to those altcoins.