Probably Litecoin. But if you want the most profit then you should mine some low-dif alt-coin and sell it. Could be the most profitable way if you mine the right coin.
Yes, this is true but keeping up on those coins and pools takes some effort, not to mention the extra trading to get some profit out. There are options, like auto switching and trading pools that pay in BTC, but for set-and-forget I would only point to solid, reliable pools.
Nothing burns more than knowing you mined a dead pool for hours, especially when diff is climbing!