I got to test Dashlane via bitsdujour (I think) a while back. I NEVER used a password manager before, so I have NO idea how to compare their service. I took advantage of their special offer for three years, paying 50 instead of 100 dollars. Yes, I know, there are services for free, cheaper or better, but I started - as I said - for the first time to use a tool that relieved me from looking up or memorize around 200 different passwords or login information for all the sites I visit regularly.
Method is simple: You login, while Dashlane is running. Dashlane "knows", you do a login, monitors it and asks, whether you want to store this special information. NEVER does it automatically, not even, if updating a known login with a new password.
The premium version can be installed on ANY device you own / use. It syncs automatically every new information to every (active / online) device. NO matter which device - including android cellphones (and probably apple as well) you use for creating or updating an entry, it will be synced with every other as soon as it is active.
Dashlane offers a multitude of features, like creating your home adress in a way it will automatically inserted in most masks using the typical fields like name, first name, street etc. You can of course create several of these.
The service: upon downloading the - then - current version, I run afoul on my Vista laptop. It simply would not install. We exchanged emails for a while and the guys at Dashlane did NOT give up until they found a working solution. Since then, no problem with updates or anything with my Vista machine. W7, android, W8, no problem anyway.
Impression: I am satisfied with the service, the product, the usablility and quite everything connected with the company and the product. But I DON'T KNOW better. First time. I like it. Yes, I took a look at KeepAss and some others, but did not even bother to install. Something just didn't feel ... right. No criticism, but just a .... feeling.
My recommendation: IF YOU are really prepared to use a service that charges money AND IF you have some experience to compare, give it a try. Test the free of charge version (not synching, only valid for ONE machine). Get a feeling for the GUI and the way it works and decide for yourself. You are about to offer your inner self to a company. Don't, if you don't feel good with it.