94, you aren't saying or asking the wrong thing. We get that same question every day.
The problem is, there really is no "right" answer.
None of them work to the level that is expected or offer the features of TDM. Hybrid is the only way to go these days. Any manufacturer that only goes one way or the other is shooting themselves in the foot.
Even the industry leader, Avaya, has many if not most of their IP Office systems being installed as hybrids. Some Avaya dealers sell these systems at full TDM setups, as in standard digital phones behind them. There's just no reason to spend twice the money to get less of a phone on the desk top.
Sorry to be so blunt, but this question rivals asking the question "what's the biggest timber that I can sell a customer to build a shed". It's all overpriced and overkill and if your company jumps on that bandwagon, you won't be asking this question again.
If your company really is hell-bent on offering a 100% IP system, check out the Vertical/Vodavi Xcelerator sytem. It is available over the counter from any supply house with no certification requirements. It's inexpensive and will give your company a good taste of a 100% IP system. Try it out and use this to determine if IP really is the way to go. At least your expense will be low to test the waters.
I'll give you a good deal on the demo kit that I bought if you are interested.
Send me a PM or e-mail if you want to try it out. Otherwise, it is going on e-bay for sale to some unsuspecting end user looking to save a buck.
