I'm having a site developed at the moment. The company is suggesting using TinyMCE in the build. Are there any disadvantages to using it I should be aware of?
Well it's a decent enough editor and is very widely used. You can configure it in many ways and the code it produces is not too bad all things considered.
I suppose the only "disadvantage" is that you can't upload and manipulate images and files directly from the editor, to do that you'd need the image or file manager addon. No great hassle because the addon is developed by the same team.
Also have you considered FCKeditor? as it supports more programming languages and I find more practical when it comes to managing files!
If some of the users require extra tags that aren't in the standard filter they will be unable to use them. In addition, any extra code that might be needed by some will be weeded out. This is great security for the bulk of users but can quickly become an annoyance to administrators, etc.