RIL is something I use to.. read it later. I don't bother to save a bookmark to a single article I am going to read and then discard. RIL also downloads the web pages into the app, so I can easily read them when I don't have an internet connection. A few web-browsers have this ability as well, but RIL is more convenient. Also lets me organize my articles to read. Plus, RIL (and it's competitor, Instapaper) are supported in a number of non-web-browser apps, such as many RSS feeds, twitter clients, etc. So I can scan headlines in NewsRack, and single out articles to RIL, launch the RIL app, it will pull down all the web pages, then read the whole collection off-line.
I generally save my bookmarks for web sites that I frequently revisit and don't want to retype a long URL to reach. I don't have a bookmark for gmail.com, but I do for my link right into this Apple forum:
https://www.mobileread.com/forums/forumdisplay.php?f=170. I also don't want to clutter up my bookmarks, constantly adding and deleting links, I keep them pretty well organized and synced across my different devices.
RSS readers, well. Play around with a collection of RSS feeds in something like Google Reader. It allows you to quickly scan headers, and some times preview text and graphics, and find articles that really only interest you. No need to browse through a whole web site. Even better when you're dealing with 20 or 50 web sites. Far faster to read the headlines.
Using either is really a personal choice, does it fit into your "workflow" on how you do things.