I used Costco Travel for cruises years ago. They were friendly, effective, and got the job done, but it took a lot of my time. They won't do anything for you unless you're on the phone, or on hold, at least that's the way it was when I booked with them. Every time I called, I had to introduce myself, give the reservation number, wait for them to find it, courtesy conversation, etc - an extra 5-25 minutes depending on availability.
It's not worth my time.
Since then I've only used independent travel agents who are comfortable with communicating via email or text. Whenever I have a question I just take a few seconds and send an email, and I typically receive a response within an hour (unless he's on a cruise! Then it's more like two hours…). For purely transactional purchases this is great.
I don't rely upon the agent to provide suggestions, creative solutions for travel, or anything beyond the basics.
So, how much is your time worth? I've almost always got something better to do than sitting on hold or talking with the fifth agent at a big firm for a simple question about linking dining reservations, or confirming a reservation, etc.
Also, the independent agents I use typically provide OBC as a bonus which is not dissimilar to Costco Travel, though I haven't compared recently. If I remember, I'll compare online next time I book.
I did read an article last week about Costco Travel, and it's now a huge business.
