I would tend to agree with Mark. As with any problem, you need the right tool to solve it. TopLink obviously isn't the right answer for every question, but if you need a JPA solution, TopLink is excellent, and the support you can get with the product is excellent as well.
Certainly if you're in an Oracle world, you really couldn't ask for a better solution.
Are there any reservations you have about the product that perhaps we could dispel?