Awesome that you're enjoying the application! Thanks for the compliments and all, it's great to read these types of posts
Same for you man, love reading comments from happy users!
1Password never stores your data in the cloud either, unless you ask it to. In your case, the Excel file is not very well protected. Lets assume for a second that somehow you get a trojan installed on your computer from downloading something and running it. It's possible they could snag your file and begin running a password cracker on it. It wouldn't take long for them to crack an Excel file with a weak password. More complex passwords might take a bit longer but not much longer.
With 1Password we use a whole host of technologies to slow the password cracking system down. PBKDF2 is one such technology. It's designed to slow the process of checking a password down. It's not perceptible to a user in most cases but when you're running millions or billions of checks it adds up to a lot more time.
Plus, we can fill that data into webpages for you. If you want to sync to a Mac you can use Wifi sync so it never touches a cloud service.
The app is free, so, give it a shot and if you have questions let me know

No harm in trying it and no harm in not trying it either. But the option is there for you if you wish.
We use the app store receipt (the one stored downloaded with the app) to determine when it was purchased and unlock the Pro features. So:
1) If you downloaded yesterday pre-version 5 release, your app store receipt says you had version 4. Install version 5, unlocked Pro features
2) If you bought yesterday pre-version 5 release, but didn't install, your app store receipt says you had version 4. Install version 5, unlocked Pro features
3) If you bought in December 2012 when we released version 4. Install version 5, your app store receipt says you had version 4. Install version 5, unlocked Pro features.
4) Buy a new phone this week? Install version 5, your app store receipt says you had version 4. Unlocked Pro features for you.
At this point if you had version 4, you get the Pro features unlocked. It follows you so long as you use the same AppleID. Now, this isn't to say that there might not be other in-app purchases down the road (there are none planned at the moment) and I'm simply covering a hypothetical, but it's possible everyone may have to pay for that if they want it.
I have no idea if we'll ever do that, but what we tried to do with version 5 was give everyone who purchased version 4 the same features they had in version 4 in version 5 without any upgrade cost.
Hope that makes sense but I'm happy to clarify.
Version 4 doesn't have pro features, it was a paid application that some people got for free due to a pricing issue. This version has all the same features of version 5 (with some changes, like CloudKit being used in version 5, but Document syncing in version 4) and of course no TouchID, Safari Extension, App Extensions, etc.
If you upgrade your device to version 5 (and iOS 8) then Pro features unlock because you had version 4. No need to pay again (or pay at all if you got it during the price issue)
See above, give with both hands, take nothing away.
Thanks for the comment. This comment is correct though the second half is opinion and I may be biased

But the first paragraph is 100% accurate and backed up by my comments above this one.