Reasons to buy Waves: industry standard, stable on most systems, several unique products, cool GUIs, good support (IME), loads of helpful presets.
Not looking to be argumentative, Eddie, certainly not with a gentleman such as yourself. But since I've already announced that one of my life's missions is warn people away from Waves, I have to refute these seemingly-reasonable reasons.
1. Industry standard
There isn't any such thing as an industry standard for plugins, and even if there was, why would I care? McDSP and SONNOX are equally-qualified candidates for such a classification, and I don't use them, either. Waves was an early entrant in this market, and many of their products initially became popular simply because there were few quality alternatives. That's certainly not the case anymore.
2. Stable
Waves only gets a C grade here, because although the plugins themselves are as bug-free as any out there, the labrynthian copy-protection scheme is unreliable. If it fails, the failure is catastrophic: you can't use the plugin at all. That's the worst kind of bug you can have.
3. Unique products
There are indeed two or three products in the Waves catalog for which there are no alternatives (I don't count the 1-knob stuff; there's a reason most vendors don't offer such things). But none of these unique plugins are must-haves. Their most-popular products, which are mostly garden-variety standbys such as dynamics and EQ, are not unique at all. I have two of their more unique plugins (Trans-X and Doubler) and I gotta tell you, I've not been terribly impressed with them, unique or not. Among my own collection of plugins, they're unique mainly insofar as they usually end up doing more harm than good.
4. Cool GUIs
Well, that's subjective, and certainly doesn't apply to every Waves product. The older plugins in particular seem to have been designed for VGA displays in the 90's, and their text is difficult to read on a modern high-res display. Nowadays the trend is toward resizable UIs, or at least multiple-size UIs, but not so in Waves Land. I will give them credit for keeping their UIs fairly clean and not cluttering them with unnecessary junk (e.g. sliders instead of 3d knobs). But "cool", nah. ValhallaRoom has a cool GUI. Fabfilter stuff has cool GUIs. The Sonitus suite has very functional, easy to understand GUIs, which rates as "cool" to me.
5. Good support
Support is paid only. If you don't buy into the bill-me-forever plan, there is
no support. None. You can't even send them an email. No other vendor on the planet has the arrogance to impose such a policy.
6. Many presets
Actually, no more than with most products, in my experience. Of course, I don't spend much time looking at presets after the first day of install. Presets for dynamics processors and equalizers are a waste anyway. I don't know how hard it is to exchange presets for Waves products, e.g. emailing one to a friend, but I'm guessing it's not nearly as easy as other products, many of whom have downloadable libraries and XML-based human-readable formats.
Of course, I agree with everything on your "reasons not to buy" list.