I've been on many a basic/good value tour in South East Asia and have NEVER rated a tour as terrible before on Trip Advisor. To summarise our tour which I think goes from forgivable (i.e. these things can happen kinda thing) to just plain old bad...
1) a mix up with guest meant we were hanging around waiting for them for 30 minutes, guest said he had given them the correct hotel address, from what I gather from reading other reviews (plus how our tour ended up) I suspect he had and it was the tour that messed up, not the guest
2) bus had to be replaced mid-tour as air conditioning didn't work - waited 15 minutes for a replacement bus
Let's put those both in the unfortunate but forgivable category HOWEVER read on...:
3) Tour guide (yes, I'm talking about you Sim) probably spoke throughout entire day (we left 8am, back at hotel around 7pm) about the temples of Angkor for probably a total of 10 minutes max - i.e. short 3 minute (and that's being generous) chat at each temple, then left us to wander around on our own at each temple without any further explanation. I think we caught him sneaking off at one of them. I enviously heard other tour guides talking about the temples in situ for more than 30 seconds :-( What do all those lovely carvings mean? Apart from one of them in Angkor Wat (and I mean one), I don't have a monkey's about any of them..
4) Lack of information about Angkor was contrasted with a HEALTHY amount of knowledge about Cambodian dating culture and other completely irrelevant chat. Don't get me wrong, normally I love a chatty tour guide who verbally goes of the beaten track, but get the relevance ratio better than 80% Cambodian modern culture and dating to 20% Angkor Wat information..
5) Driver and guide had NO idea where any of our hotels were and that was with Google Maps. Slowly one by one (of the 5 of us that hadn't left the tour mid way through the day) we got more and more lost and all of us got out and walked back to our hotels in frustration
6) Sim was kinda rude at times
7) ICING ON THE CAKE: Me and my other half were the last ones standing (well sitting) in the van as we didn't know how to get back to our hotel. Sim said he was 'just going to get his motorbike and follow the van' which translated in reality to - divert us via head office, pick up his motorbike, give quick instructions to non-english speaking driver and scoot off without saying bye back home (he probs wanted to get back, we did too though). I suspect we were holding him up as POINT 8) when we on our sunset temple viewing (part of the itinerary) he was rushing us / annoyed it seemed we weren't down before sunset. He mentioned earlier he had evening training, so I suspect we were ruining his plans..

All in all, for a day where you pay for a tour plus a hella lot of money for tickets to Angkor Wat - this really was a below average tour..

I'm very ungry, we had ask shuttle transport from Model Resort to airport departure terminal and the driver leave us at arrival terminal. We had to walk with our lagguge and hand bags 100 mts, under a very hot weather. The taxi driver triky or stupid, maybe both, because he could stop at departure door

My tour to Siem Reap with my fellow friends, has been a wonderful delight to my eyes and mind. The tour provided me with much experience that helped me to understand and appreciate the value of culture and heritage of Hinduism and Buddhism. The tour was scheduled to enable us to visit almost all the important attractions. Thanks to our guide Mr Chantey, for helping us to plan our journey within the area. Other than that he also helped us to select good restaurants for our main meals. As he explained about the places, he allowed us to discuss and question for better understanding. Mr Chantey has also been very professional, at the same time behaved friendly, polite, kind, helpful and understanding to us. This trip is a memorable one on the positive side. Thank you for the delightful experience.