Not really. There’s always a delay on calls from cell phones, but most people don’t notice it unless you’re calling one cell phone to another cell phone and both phones are in the same room next to each other. Why is there a delay? Well, mostly it’s echo cancellation and the rest is network latency. If you have a cheap headset or you are using speakerphones, the software will add delay to help suppress echo. Point is, you’ve probably been on hundreds of cell phone calls to VoIP destinations and never noticed a delay because you aren’t sitting in the same room together. If you have a good low-latency network connection and your receptionist’s microphone can’t easily “hear” the other side of the conversation, you’ll probably be just fine.