It came free with my Sony PCM D50 and was wondering if it is a software people use for sfx editing and sound design. I use Pro tools 9 but this software may be quicker for editing raw soundfx and designing a sound. Your opinion?
I use soundforge quite alot, AFAIK it's a pretty common tool in game sound design. The reason being that you can play, edit, compare and master multiple single files, either individually or as a batch. It's great for seeing if all you individual footstep sounds or explosions have a similar RMS and tonal constancy, and making tweaks and edits after bouncing from your DAW before putting in game. Also if you bounce e.g. a 2 minute file of whoosh sounds, SF is a great place to sample accurately edit before putting them in game. Looping sounds in SF is also pretty nice. I also know alot of people who use it for batch dialogue editing and processing for games. I have never really come across a decent alternative that can do all the things that SF can do, especially in the ability to open view and edit multiple single files at a time. However having said all that I am not a great fan of the software. It has a habit of crashing and the standard plugins don't sound good. Getting back to your question, I would say yes it is much quicker for editing raw sound data, e.g. pulling the sounds out and creating new files from them, but any kind of metadata work or processing I would leave to Wave Agent and pro tools.
Sound Forge is lightning fast for individual file editing. However, every new release seems to become slower and even more buggy. SF10, the latest, is worst of them all. I actually had to e-mail Sony support asking for a SF8 license because I hated Sound Forge 10 so much (the surprising thing is that they happily gave me that license).
I do like Sound Forge for individual file editing, and I use it a lot - especially (but not exclusively) on dialogue. It draws wave forms very clearly, so it's perfect for surgical editing. The batch editor is fast as well, although it can be buggy, you kind of need to know how to bypass its quirks. All the things Richard pointed out here earlier are true as well.
On a side note, it may be worth looking into Adobe Audition if you are in the market for a audio editor. It's not as fast as Sound Forge, but you get much better built-in effects and a fantastic resampling engine in return. Moreover, the main reason to get Audition is for its spectral editing tools - quite similar to Izotope RX in fact. Depending on what kind of work you want to do, Audition is the better choice. I own both SF and Audition for this reason. I'd say, Sound Forge works best for fast, basic but important editing, whereas Audition is more of a creative tool which can do some fairly unique things.
I've touched on Sound Forge a bit and like it a lot, but I know a few guys who reckon something like version 4.5 was the last good one (I forget why). They're using Wavelab nowadays FWIW.
Hope this helps!
I use Sound Forge 9 quite a lot for initial recording of disc and analog tape transfers--it is easy to set up, and can use ASIO drivers compatible with my Digi 002R interface. It is OK for general editing, but if you need good crossfade capabilities for editing music, Pro Tools is a better choice.
As Daan Hendriks noted, Sound Forge has suffered from feature bloat with increasing revisions, and Sony has not been good about fixing bugs. Still, it is a very useful program, fast to use, and will accept a wide range of third-party plug-ins.