I'm not sure what there is to manage. I've got several dozen domains. I use my registrar's tools (all domains at a single registrar) as well as my hosting company's tools (all domains at a single hosting provider). That seems to work OK for me.
Many reasons to use domain management software...let me mention four:
1) I want to track domain names that someone else owns, and sort them by expiration date.
2) I want to track domain names that I'm considering buying, and add notes like "Mark and Denise liked this name, so I should probably buy it."
3) I (unfortunately) have my domain names at different registrars.
4) I want a brainstorming tool to help me find available domain names based on keywords. Some programs let you enter keywords and they'll create a list of matching domain names and then check their availability.
Also, for managing just your domains, I recommend using the option that is being offered recently of making the expiration date the same for all your domains. This way you don't have to keep track of renewing on random dates.