I used them for my everest base camp trek. I didn't rate them at all.
The local guides they used were fantastic, however Intrepid didn't provide a list of sufficient gear for the time of year our trip was (late January - freezing), just a generic list. I called them to clarify that the list was correct before I started shopping at home and they assured me it was adequate for the time of year I was travelling. As a result no one had the correct gear and it cost us a significant amount to get it all last minute in Kathmandu or as we were travelling. Not to mention that we still had to carry all of our other gear that wasn't warm enough.
They also did not disclose the expected (read compulsory) tip we had to give to each tour guide (3 of them) and each porter (another 3 of them).
All in all it resulted in a very expensive trip - and when I sent them a follow-up email, they didn't respond.
Wouldn't use them again - try GAP instead, they're great! almost 7 years ago