Launching Catalogue brings up a daily "cover" with several highlighted catalogs. Swiping left opens the catalog and shows areas that are dedicated to each store -- you can scroll through the many catalogs by swiping left and right. Tapping on a specific store brings up a more detailed list of items that are currently for sale. For example, I was attracted to the Sur La Table catalog because of the emphasis on grill items right now.
I've been looking for a grill pizza stone for making my own pizzetta, and was thrilled to see a pizza stone with a stainless steel frame in the catalog. I tapped on the item for more information, got a detailed description of the stone, and there was a Visit Store button I could tap to go directly to the Sur La Table website to order it. Pretty cool.
The app has a search button for finding anything in the "meta-catalog," and it worked well when trying to find such diverse items as Ecco mens shoes, California Syrah wines, and shotgun shells. That's a pretty broad range, and The Find's Catalogue led me to listings for all of those items. The 'My Catalogue' feature is basically an aggregated page of your saved favorites across all catalogs + a list of recently viewed items; it's functional enough to help you track your stuff.
Unfortunately Catalogue does not seem to multitask correctly on the iPad, so it won't remember where you were if you switch away to check an email or send a tweet. It also doesn't cache catalog content, so expect to wait a bit each time you launch the app for the products to load in; of course, both apps require Internet access (3G or WiFi) to show catalog content.
Being a 50-ish balding guy, I have no interest in women's fashions or kid's clothing. Catalogue offers a way to filter out those areas, although I still ended up with some of the catalogs that I really didn't want to see. A way to click on a specific catalog and say "don't show me this again" would be wonderful.
Catalog Spree kicks off with a view of all the catalogs offered in the program, so you can dive into the one you want with a single tap. You scroll through the catalog a page spread at a time, making the experience a lot like... well, reading a catalog. You can bookmark a catalog page to get back to it rapidly if needed, or share a catalog by email or Facebook. There's also a folio view that shows all the catalog pages at one time.
The iPad screen isn't big enough or adequately high-res to let you actually read the product descriptions, so you tap either the picture or the text block for a product to bring up a legible detail view. From there, you can see all the other items on the page in detail as well, plus quick-access buttons to mark an item as a favorite, email it to a friend ("Hey, Honey, is this what you wanted for the dining room?") or post it to Facebook. You can also set notification options to flag you by email/push notification when a new edition of that catalog comes out, or when the vendor releases a special offer. You can also quickly suggest new catalogs for inclusion by sending an email from inside the app.
Remember that big missing feature I mentioned? Catalog Spree, surprisingly, has no search function -- not per-catalog, not across catalogs, nada. The app's faithfulness to the print catalog experience may have gone a bit too far in this case; while browsing is nice, search is pretty much necessary.
Like Catalogue, Catalog Spree jumps you out to the vendor website when you want to place an order. This feels a little awkward in both cases, and you have to manage your shopping carts independently for each catalog vendor.
Both apps are free, so give them a try and see which one suits you better.