Best Idea is to sign up for all the free trials. If there is a research tool without a free trial then they will have a 30- 60 day money back guarantees depending on the vendor, so you can use their cushion period to evaluate the product in depth. I did this until I found which tools I felt were the best for my research strategy and then bought accordingly. If you do it this way before you buy for real you will be getting all the research you need done during that period for free. So it is important to plan what you want to find out before you start to buy these tools or get the free trials so when you do, you make efficient use of your time.
Remember ..time is money!