The low limit tables at Pokerstars (and at UB, for that matter) are as soft as any other online poker room’s low limit tables. I’ve played on at least 20 different online poker rooms, and I’ve yet to see any tough competition at any of them until I started playing the higher limits (above $3/$6).
The CPA at Pokerstars is on a tiered structure, so you get a higher CPA (up to $300) if you deliver more players. The tier is outlined on the site:
If you don’t like CPA deals, then it’s probably not the right program for you, but Pokerstars is an excellent company to do business with, especially if you’re seriously looking for “honest” poker rooms. Pokerstars has an excellent reputation for integrity.