What do you like best?
This is a great FTP client! It is very stable and I have never had any issues with it. I use it all the time at work, almost on a daily basis, and I have never been dissatisfied with it. I like the fact that it keeps track of the total amount of data that you have uploaded/downloaded in the past, so it tells you on the Splash Screen that you've transferred X number of GB since you installed the software. I like this feature and think it is kind of neat that it shows you how much data you have moved in the past. Let's you know you're getting your money's worth out of the product.
What do you dislike?
There's isn't much that I dislike about this software other than the fact that it isn't free. It's great software and works extremely well for both client and server applications. Other clients like FileZilla are free from the client standpoint and do well, but WSFTP has more and better features.
Recommendations to others considering the product
Get a demo of the software before you buy it, possible from someone who uses it currently and can speak to it's features and functionality.
What business problems are you solving with the product? What benefits have you realized?
We use WSFTP for both client desktop connections as well as hosting our Secure FTP site for our business. From a server standpoint it works extremely well and is flexible enough that we are able to use it for all of our FTP need.