It leaks memory, and it's kinda a memory-hog — I wish they'd have used Ada or Eiffel in their rewrite.
Ada — known for its use in safety-critical systems, has a reputation for high-reliability systems because of its type-system.
Eiffel — Known for being the preeminent Design-by-Contract language, giving a lot of thought to interfaces.
just switched over to Opera to give it a go and it seems to work just fine... has a debugger built in and has add-ons like ghostery and lastpass for those that use them.
I'll give you that it's a memory hog, sometimes taking up a half gig depending on how many tabs I have open. However, FF hasn't "leaked memory" in years. A TRUE memory leak is one where RAM is consistently lost to the process until the process either locks up or the system crashes. The last iteration of FF I can recall that had that problem was way back in the FF15 days, and that was due almost solely to poorly-written add-ons and extensions.
FF is it's own process. It has no hooks in the OS, hence its utility on almost any platform, and it runs independently of the OS kernel including its own certificate stores, Java kernel bucket, and application rail. FF is a safer, more stable browser than IE and while it's not as streamlined as Chrome, it's much better at error handling. FF is a memory hog, because you're essentially running a mini-OS over top of your OS kernel.
Mozilla mostly makes their money through advertising. Given their profile in the open source community, however, FF would continue to thrive even if Mozilla, as an entity, was at 1/10th its current value. Remember that Mozilla is a standard-bearer for much of the open source community. They're not a for profit entity, so their value isn't really at issue here, I believe.