I've been experimenting with Springpad and Evernote. I've actually used Springpad in a limited way for several years. I especially like using it for products - I have a folder for books and another for wines that is shared with family members. I love the ability to scan a bar code and (90% of the time) add the product, with reviews, links to purchases, price comparisons, etc. Very nice. I've also used it for a travel checklist and a few other items. But, not a major effort with it.
I've looked at Evernote several times, but never been hooked. However, due to my colleague Larry Richard's recommendation, I've taken another look. And, over the holidays, I've played with both and done some looking at reviews and blogposts about each.
I started off leaning to Springpad, partly because I was already familiar with it, partly because Evernote just didn't make as much sense to me intuitively, and partly just because I like to try out the newer and less-used product. As I dug in, I thought I was really going to like Springpad. First, you can look at items within a folder - notes, products, etc. - in a number of views and sorted different ways. And this includes a free-form "pinboard" sort of view that lets you move things around. LOVE this for organizing ideas!
Also, Springpad claimed the ability to sync with Google Calendar, so I could handle appointments, engagements, events, and so forth as items within Springpad and the see them automatically on my Google Calendar. I thought this might let me do a better job about keeping all information about an event in one place, so I liked this. Unfortunately, it turns out this capacity does not work and an inquiry to Springpad support revealed that they intend to remove it from the feature list. The more I think about it, the more I agree with them. I can keep info about an event in either Springpad or Evernote without any real need to link it to the calendar entry - and both are readily available on my Android phone.
Springpad - the Bad
As I played with Springpad, however, I quickly realized that having lots of folders would become unwieldy because Springpad does not allow for putting folders within folders. Evernote does - it calls them "stacks."
Evernote - the Ecosystem
So, slightly disappointed with Springpad, I discovered two products for Evernote. They're part of the Evernote "ecosystem" - products built to work with Evernote due to its huge user base. The first, Mohiomap turns your Evenote data into "maps" that remind me of those produced by The Brain (another product I've played with but which has never hooked me. I like Mindmaps (even took my notes for the MAPP program in them), so this hooked me. Then I found CardDesk! It gives all the "pinboard" capability of Springpad (and maybe more - haven't finished playing with it). Suddenly, most of the advantage I thought I had seen in Springpad disappeared. Both of these products just worked, right out of the gate. And, I'm interested in experimenting more with some of the Evernote ecosystem products, perhaps by connecting up Expensify, Evernote, and Freshbooks.
Evernote - the Functionality of Stacks
Finally, as I began to dump more and more notes into each, I began to see the need for more organization, and Evernote's "stacks" gave me that.
So, what will I use?
Well, like some others (1, 2), I'll likely use both, but I'm going to lean to Evernote for notes about ideas, documents I've created. Springpad will likely be my goto for structured data - products, checklists, etc. and for coordinating with family and friends. It is "friendlier" on first contact and folks are often sold just by seeing the barcode scan feature one time. And, in sharing information about projects with my wife (vacations, for example), the Pinterest like visual nature can be very helpful since she is more familiar with that product and not nearly as in to learning new apps as I am.
As always, your mileage may differ!