Hello po. I have a Sakura AV1600. I bought it 3 or 4 years ago, it's still ok. The ProLogic decoder is legit. Dolby has licensed it. The DSPs are working too. So far, I've only seen 2 Sakuras that have legit ProLogic. AV1600 and AV1800. I've been told, and have seen on catalogues, that there are other models that are Dolby licensed, although, as I've said, I've only seen, tested, and installed those 2. I like to listen to my audio cds on this amplifier in ProLogic mode coz it seems to generate a wider soundspace for audio cds, I personally think it sounds better than my Yamaha DSP-AX430 in ProLogic II. So, to answer your question, for their price (mine was 3.5K), it's a great amp for the not-so-rich home theater enthusiast. Now, the 5.1 channel input at the back, you'd have to have a DVD player with a built in DD & DTS decoder, and you'd have to switch your dvd to 5.1 mode, that's the purpose of the 5.1 input. Being able to enjoy dvds without buying a digital amp. Note that I said DD & DTS decoder, because I installed another AV1600 for a friend using a Xenon DVD player, w/c only has a DD decoder, not a DTS decoder, so the movie goes silent when we switch the audio to DTS mode, while mine decodes both so... my advantage there. Another note, the AV1600 is better than the AV1800, although the latter has more inputs and switches for speakers A & B, the surround volume in 5.1 mode is not loud enough even at max. My friend and I had to buy a separate 2 ch amp to amplify the surround channel. Although, I don't think the AV1600 is still available. I think they stopped making it. Sad, coz it was one of their finest, at least in my opinion. Hope this helps you guys, TC.