I use both Tortoise and Subclipse concurrently. I tend to grab alot of open source libraries from code.google.com and Tortoise makes it a snap to checkout, and even make copies using SVN Checkout. While working with large team projects Subclipse is the way to go if you're working on projects within Eclipse, once your code is checked out you can still use tortoise to run all sorts commands on the SVN, as well as Subclipse commands, without any major issues.
