I recommended Solo to him because I was planning on kick-starting him. Benefits of being the Father-in -law. :-)

There are a few benefits to pool mining.

1. Lower cost of entry. You can start with 0 and just starting getting paid as you earn.
2. Mildly simpler set-up. IMHO.
3. Regular income feels pretty nice.

There are also some benefits to Solo mining.

1. You get your RAC and BOINC credits tied to your own CPID, which gives you that warm fuzzy feeling of accomplishment, not to mention the insatiable urge to re-purpose old computers as the competitiveness kicks in.
2. You get to VOTE. You have to be tied to your own CPID in order to vote in the polls.
3. I swear I had a third one but my mind went blank.

Not a definitive list there, but it's a start.