At Dialogic now have many overlapping families of products, thanks to the product families from all of the contributing companies to our corporation (Intel, Eicon, Brooktrout, NMS, Excel Switching etc). It's always useful to have more than one thing in your toolbox, and as they say "to the man with only a hammer, everything looks like a nail." But one of the fundamental choices for customers is whether to build a solution using an off-the-shelf appliance approach, or whether to construct their own using PCs, boards, SDKs and custom software. In other words, it's like choosing between a meal that is ready made (e.g. a microwave burger) or making your own from raw ingredients.
When you go the off-the-shelf route, the advantage might be to go more quickly to market with your idea, and perhaps the extra expense of an appliance is justified by arriving before your competitors. On the other hand, when you construct your own solution, it might take longer to do the engineering, but there is more flexibility in the product to meet specific user needs. Also with this approach much more of the final intellectual property belongs to you (and not Dialogic), so this may be an asset in itself.
The downside of engineering your own product is that the cost of ongoing maintenance of that code will remain with you, where an appliance you could expect the burden of maintenance and enhancement to fall on the vendor. There's no absolute answer which approach is right. Some companies value intellectual property above all, and will want to control as much as possible; for other companies their own product differentiation might be based on other business factors and not so much on engineering.
To return to the cooking metaphor, we know that McDonalds is a huge worldwide success, and their great triumph is to create commoditized and accessible fast food. It's the same wherever you go, and the price will never be that much of a surprise. However, we can't live on McDonalds alone, and sometimes it's nice to go out to a restaurant that is one of a kind; there is always room in the market for a custom product that offers excellence in a focused way.