Solo Mining vs Pool Mining for users with high computing power Let's say that a user has a decent amount of computing power. At the current difficulty of 1777774.4820015, he could have for example 10Gh/s (he would earn around 5 BTC per day according to a calculator).

Is it more profitable for him to solo mine or to pool mine? What are the differences in this situation?
It completely depends on the "pool fee". Theoretically, with a zero percent pool fee, solo mining and pooled mining should, over the long term, produce precisely the same revenue. The only exception is that some (most) pools keep the transaction fees for themselves.

If you mine solo, with an expected 5 BTC/day take, that will mean on average you'll mine a 50 BTC block every ten days. It will be completely random though. You could mine two blocks in a day. You could go three weeks without a block. When the difficulty changes, not only will the amount you get paid change (that always happens) but the time between payments will change drastically as well.

If you mine in a pool, you take the pool fee right off the top. A 3% pool fee means you make 3% less. Also, most pools don't pay transaction fees. But your revenue is more predictable. You'll get paid on a regular basis and your payments won't vary much (until the difficulty changes, of course).

One advantage to solo mining is that it's more reliable. Pools have outages and have had a problem with denial of service attacks lately. Mining solo, you aren't relying on other people's systems to keep your mining going. If you pick a very reliable pool, or use a mining proxy with a "fallback pool" configuration, this isn't a major issue.

One advantage to pooled mining is that you get to use the pool's tools. These include things like web-based control panels, alerts, and so on.