Doktor is working on a coin switcher (YAY!), but until then, you can try out this one,
Coin switchers are overrated.
None of them are giving you an edge. There's always going to be somebody who's faster or more powerful than you and will "steal" your blocks from all those useless Yiimp pools. Add to that the fact that you don't get proper market data (you usually only get "last paid price" from the exchanges as opposed to "bids"), and massive latency (hours!) between the moment the switcher decides a given coin is most profitable and the effective time your mined (and matured) coin finally gets exchanged, and the whole exercise is completely ludicrous.
The good trading/switching algos out there are already flattening the market. Look at the various profitability calculators online and check with your hashrate. On average, the profitability difference between the 5 top coins will be within a negligible 5%.
Coin switching has been very necessary for me, I do manual switching though.
I may switch based on just difficulty alone without looking at price so I mine more of a coin, or I may switch to a valuable coin that I convert to BTC. I use this proxy so I'm able to switch coins using my mobile and it's quite inefficient when switching through a remote desktop solution and pressing "p" button to reach the coin you want, only to have your hashrate drop and wait for a few blocks to get it back up.
The automated one I'll try to do will let you decide based on difficulty (do not mine when difficulty is so high), or a combination of difficulty and price, and maybe something in between. I hope Doktor's version also takes account this, sometimes I don't care about the value of the coin, because as you say the price is very hard to determine (Solace, anyone? It switches between 2 or 3 satoshis massively deceiving the profit calculators, however, I just switch to it if I can mine enough of those, not looking at the price) And low hashrate coins are very vulnerable to pile-up's due to coin switching of mass hash-rate sources (nicehash etc.) so you may be getting very little half of the day until powers that be pile up on another coin. The (difficulty) / (weighted exchange rate) approach could be a nice compromise for switching (esp. for low hashrate / per block or small gap difficulty adjusted coins)
Coin switchers are a meme. Very difficult to properly monitor accurate market data + nethash spikes with low latency.