|If it were me, and I do know Cisco's IOS and how to program their switches, I'd still recommend against buying Cisco. There are other products out there that are every bit as good that don't require the same level of knowledge to manage/maintain and you won't get skinned alive on the support contract.|
I'd be very curious why he thinks he needs Cisco switches. After all, if he were capable of setting up the switches himself, he wouldn't be hiring you to do it for him. So I suspect some Cisco fan told him Cisco's were the be-all, end-all in switching.
You can tell your client a professional network technician with 16+ years experience in industry who has worked with Cisco products said so.
Having said that....................
It's his network and his money so he can spend it how he pleases. Just be careful you're not buying equipment you can't manage for him or you'll lose the contract in the end.
Google the specs on the Alteon switches your client is presently using. Then go have a look at Cisco's website and find a switch with the same features. That's what I would do.
It matters not how straight the gate,
How charged with punishments the scroll,
I am the master of my fate;
I am the captain of my soul.