InsaneJournal

InsaneJournal (IJ) is a long running LJ clone and the largest. It is run by squeaky.

Differences from Dreamwidth

Many feature-based differences are the same as the ones listed in Dreamwidth changes from LJ, so this focuses mostly on the other differences.

IJ has many more icons for all levels of account plans. DW's free account has 6 icon slots.
IJ has cheaper paid accounts, and frequent permanent account sales at $40 or so. DW has had only one permanent account sale, at the beginning, at a much more expensive price point and doesn't intend to do another. IJ also has a greater variety of paid account types, some that only focus on extra icons.
IJ doesn't require invite codes, while DW requires either an invite code or the purchase of paid time to create an account.
According to the site stats, IJ currently has a greater number of active accounts.
IJ is a fairly stable platform feature wise. This can be an advantage for someone who is satisfied with its current offerings and is unattracted to a service with rapid changes and developments.
IJ has longevity. It's been around for a long time.
DW has no schools directory.
IJ is much more familiar to people from LiveJournal.

IJ isn't as stable as DW in day-to-day operations. (However, DW does run into some small bugs and glitches during code pushes.)
IJ doesn't have anyone working on it fulltime, while DW has 2 dedicated staff admins. DW also has a bigger personnel/volunteer base and there are several technical admins able to address site issues. In addition, it has an organized group of coders working on bugfixes and improvements, and a larger support group.
IJ is slow to implement any new features, and sometimes finds it difficult to find the time to analyze and fix bugs, even serious ones.
All users can on DW can create feed accounts. On IJ it appears this is a paid feature.
IJ's funding can be a little hand to mouth sometimes; DW has a higher and steadier income and money saved.
A paid account is required to do S2 customizations on IJ; free users on DW can have one S2 layout they can edit.

IJ does have some Project Wonderful ads to help fund costs, although they are not displayed on or to paid accounts.

Dreamwidth can crosspost to IJ as well as import posts and comments.