I researched this alot before i actually started using SS. Basically I ran runescape on a Intel Celeron 600MHz, 64MB ram, laptop. It ran ok on low detail, but whenever Jagex's adds would refresh, it would cause my laptop to load for like a minute, bringing me to the login screen and i would have to relogin. Nothing bad really, just a pain. So I looked around, at the runeHQ xplorer, and Runescape toolkit (which is never going to be completed at the rate its going), and I looked at Swiftswitch. When i first started looking swiftswitch was on an independent website, so playing it safe I still decided to use the official runescape client. But then a few weeks ago, Swiftswitch got supported by
http://www.runescapecommunity.com and people started talking in the forum in there, FAQS and other posts about how it is legit, JAgex messages abotu how its legal, and many people have scanned it for trojans, keyloggers, etc... So I downloaded swiftswitch, from Runescapecommunty, and started using it. Now I hav ebeen using it for nearly a month, and its great. I mean no it doesn't get rid of the 30 second world switching, but still sves me a lot of clicking and page loading, also if I need a calculator quickly or a price guide even a map location, its all built into the menu system they have. Plus my laptop doesn't have to load the adds, therefore it never makes the processor hang on loading new adds. It's a really great program, but one thing I suggest is ONLY download it from the official runescapecommunity link, located in their forums, because 3rd party sites could have attached keyloggers to it. Unfortunately i believe
http://www.runscapecommunity.com website is down at the moment.