The person you have been speaking to is correct. The HL-DV7W is very similar to the DSR-500. The recording section for the Ikegami is made for Ikegami by Sony (as far as I know). Both are DVCAM. Many feel the Ike has a better picture than the Sony. Roger Macie has a write up on the HL-DV7W on his site if your client is familiar with him.
An important difference between the DSR-400 and 500 is that the DSR-400 is 4:3 only. The DSR-500 is 16:9, 4:3 switchable (as is the Ike). You'll loose a little on the wide end of the zoom if you shoot with 4:3 on the Ike HL-DV7W or DSR-500.
Unless your client has a thing for Sony, the Ike will perform up to his expectations picture wise.