The problem is a straightforward and common one: limited memory, my preferred username (my main email address or a variation on my Real Name) are either not allowed (in the email case) or taken (in the realname case) everywhere I have an account. That in combination with the security issue of password reuse has led me to search out a Password Manager. The major choice with password managers, from my perspective, is whether you want to pay a subscription and have someone store stuff on their server or whether you want to avoid paying a subscription and/or not have someone store stuff on their server. The latter choice seems to involve doing all the syncing yourself, either on your home wifi network if any, or through something on DropBox that I don't understand and didn't feel like trying to learn at the moment. I opted for the subscription choice. I suspect if you weren't Apple Centric (that is, if you were running a Windows laptop and/or Android or RIM phones), you'd pick something other than LastPass. But I'm Apple Centric, so there you go.
Apparently the early adopters for password managers also demanded Form Filling capabilities, so LastPass and other password managers and many of the reviews of same focus on Form Filling capability. I could not give a shit about form filling; I just didn't want to have to maintain a notebook or spreadsheet with all my account information in it (keep it up to date, don't lose it, maintain security on it, etc.).
I had some concerns going into this project: would it become such a crutch that I forgot everything and if I did and it broke would it be the end of my world? To mitigate that fear, a friend of mine reframed the concern by pointing out that I could always go back to my old way of doing things: just reset the password. Also, I kept some of the most sensitive accounts out of the manager. My friend also pointed out that this isn't a crutch, any more than carrying a cell phone is a crutch. Since, back in the day, I was a rabid Treo fan, that made a lot of sense to me.
Because I am Me, once I got all the common accounts into the manager, I proceeded to poke around at the accounts I probably should remember how to access (EasyPass and similar) and set them up, and then dug through things I have paid for to access genealogical information but use rarely because I've forgotten the userid/password combo and got them set up. Turns out this particular crutch is sort of bionic: way, way better than my brain on the Best Day Ever.
Only one account was persistently unavailable. My JetBlue TrueBlue account had been de-activated due to non-use, and the password reset function was not working. It took three phone calls to resolve, and they ultimately reset the e-mail address on it. I do not believe that the JetBlue e-mails were getting lost on my side, but whatever. It works now.
LastPass on the iPad doesn't work the same as it does on a Mac, because on the Mac it is a plugin and the iPad browser doesn't support that. I have not tried the bookmarklets feature yet. Instead, LastPass on the iPad has a built-in browser which R. says is the native browser with a wrapper around it. *shrug* I've run into some problems using it that I don't fully understand, but none of them are particularly worrisome. I have not attempted to use LastPass on the iPhone. Yet.
If you are struggling to manage dozens of userid/password combinations that you only access occasionally but really don't want to de-activate (I suspect the increasing complexity of our family travel in conjunction with the genealogy habit is what did me in), a Password Manager might really improve your life. If you hate filling out forms, bonus! The forms don't really bother me. This was a tremendously worthwhile project. I will continue to work at it, and may amend this review to reflect additional experience.
ETA: Meant to say on a marginally related note: wow is it impossible to get Logitech to stop sending email. I've unsubbed from their crap repeatedly. It does _not_ go away. I've even tried adjusting the email address to account of possible variants that send to the same address (viz. with and without the . in a gmail email name).