Besides the fact that you didn't answer my question on how the built in conference bridge works on the other phone system, I agree with the sales pitch. However, the other phone system sales folks do the same.
I have learned that you can't hold a phone system as the "bible of features" and compare every other system with it. I guarantee that you will find very nice features on the other system that the "bible" hasn't even dreamed of. You pick a system on the needs you have and if your needs change then you need to redesign and possibly add new features and hardware.
I make a living designing, installing and supporting all CISCO unified telephony products and I take it with a grain of salt when people seeking help on this forum knock the rest of us and what we do. There is a reason cisco is the best selling product out there and it is displacing everyone else out there. You can call it marketing, a scam, stupid people bying a crappy product, but the bottom line is that it is robust, support is outstanding, especially compared to other manufacturers and if you know what you are doing it will meet the five 9's that all the TDM discontinued products are hooting about.
I choose to work with the cisco products, it is a choice I consciously made. I have worked with Mitel and Nortel in the past and I wouldn't look back not even for a second. Less headaches, better pay and a career path that will be around for a little longer.
Again all the above is just my opinion and nothing more.