I can't stress enough the importance of a clean and well-maintenanced system. But please do not install cleaners or uninstallers for your Mac. The only product I believe you can get away with using is CCleaner.
Products like "Dr. Cleaner" and "App Manager" may be allowed to be distributed even in the Apple App Store, but they have unexpected results and there's no liability for data loss or system failure.
Take my word for it, you'd rather manually maintain your system and take the 30 to 45 minutes that it may take every few days than have to deal with OS corruption--not everything can be fixed after it's been corrupted.