Since a couple of ppl have asked on here and via PM, here's a comparison on MY experiences SO FAR at Chan and NsM (I have met with each once). Again, this is MY experience, YMMV.
1) NsM (I'll just keep saying NsM instead of Mina and Dino, but they are who you will be dealing with) is more responsive over email to set up the initial appt, and since. Sometimes and email will go unanswered, but generally they respond quickly and are very friendly. With Chan, it took a while (a few days and a couple of tries) to set up an app't. I also emailed them a couple of days ago after my appointment concerning some details of my order, haven't heard back yet.
2) When you meet them, NsM will say hello and kind of meet you a little bit first, even if they are busy. Then after you tell them what you want, they'll let you sit down with the cloth books for a while and take a look - likely you won't be the only one there and they'll be busy but you get the impression they're happy to have you there for as long as you want to stay, and will answer whatever questions and give whatever input you ask for. They will likely encourage you to come see them in Naples some time and are just lovely people to talk to. They clearly love what they do and are very proud of what Naples represents in the sartorial world. Chan has a more professional demeanor, cloth books are very organized in their layout, same thing where after you tell them what you want, they recommend a couple of books to look through and will answer questions and give input. I found the SA knowledgeable, helpful, and courteous. When I first arrived I was the only one there and even when others arrived later, the atmosphere was very orderly and boutique-ish. I never felt like they were nudging me out the door, but it is more scheduled and directed. As I said, they're very courteous and respectful, but they're not making friends. It would have been a bit odd if at the end of our appointment they had encouraged me to come see them in HK some time. I'm not knowledgeable enough to give a verdict on the cloth selection available from each, but it seemed like Chan's selection was a little better (but again, I'm not a cloth expert, and NsM certainly had plenty for me to look through).
3) With NsM, they'll take a few measurements, and then some photos/video of you, but not much. Nor will they ask you much about the details of your garment. I'm sure some of these things will get worked out at the fittings, but at this first meeting they just asked me single or double breasted, how many buttons, how many vents, and type of pockets. If you want some deviation from their usual type of shoulders or lapels or something, you'll probably want to speak up for yourself as they may not ask you. Chan, by contrast, will take a LOT of measurements, both of the garments you're wearing (they instruct you to arrive wearing a jacket that fits well), of your body, and then also on some kind of test garments they fit on you. They'll ask you if you want your jacket to be shorter or longer than the jacket you're wearing, lapels smaller or bigger, etc.. They'll also ask you all the finishing details like what color lining you want, if you want your name or initials on the inside, type of buttons, etc.... Patrick Chu clearly knows what he's doing and after 15 minutes of him working on you with a measuring tape, you have every confidence that he will make a nicely fitted garment.
As I said, I will give a complete report at the conclusion of the process with each. Both have been very positive experiences so far, and there's a good chance I will continue to do business with each for the foreseeable future.