Linux is understandably popular as an operating system for embedded systems. SoC vendors in particular like to supply a Linux "distribution" that is tailored for their platform. This "distribution" usually includes the binaries for an appropriate toolchain. In my opinion you should stop using this toolchain long before you are ready to release your product.
The binary toolchain supplied by your vendor is easy, it might even be statically linked making it even easier to use. Just plonk it in the right place and everything magically works.
1. One day you're going to have a bug. That bug will either require some debugging in files that are supplied as part of the toolchain (ld.so, glibc) or require you to make some modifications to the toolchain in order to help investigate the problem. You might even find a toolchain bug that you need to fix. This sort of problem is almost guaranteed to occur at a point when it is deemed too dangerous to switch to a self-compiled tool chain. That's if your lucky and you have the source code for the tool chain and it actually compiles for you.
2. In order to comply with the GPL you need to release working source code for certain bits of the tool chain anyway. How can you be sure that this stuff actually compiles unless you have done so yourself?
3. You need to support your product long after your vendor has moved on to another generation of chips. Will their toolchain still work on whatever host operating system you are using then?
So, at the very least you should get the source code for the toolchain from your vendor and then compile it yourself. Use the version you compiled yourself. This leaves you in a much better position when the unexpected occurs. If your vendor won't give you the source for a toolchain they've given you in binary form then find another vendor that understands software licensing.
Of course you could just compile your own tool chain from scratch and use that but creating cross-compilation toolchains is certainly not easy - perhaps that subject is worthy of a future post.