This may seem crazy because I just welcomed a beautiful, near new Steinway B acoustic into my home, but I also want to upgrade my digital practice setup. Even though I of course am on cloud nine when playing the B, the reality is that I have to coexist with my family who need to sleep sometimes or use the parlor, so I will still need the DP to put in what I feel I need for adequate practice time. It's also easier to record from a digital for self evaluation purposes.
My current DP setup is a Yamaha Arius (YDP-162) feeding a MIDI output to a computer running Pianoteq. I am quite satisfied with Pianoteq after spending the time to set it up correctly, but I feel a better keyboard would be in order. I don't need a full-on synth or a standalone piano, just a good keyboard with the full complement of MIDI outputs, such as after touch etc. My question is, what would do you think is the most authentic feeling MIDI keyboard out there when it comes to the action?

Define "MIDI keyboard" please. Are you talking about a "MIDI Controller" which is a keyboard that only generates MIDI output and has no sound generator and speakers? If so, the best is currently the Kawai VPC1, which has a rather heavy action.

If you mean by "MIDI keyboard" any keyboard that generates MIDI output whether or not it has a sound generator or speakers, then it is probably the hybrids: the Yamaha Avantgrand N1X, N2, or N3X, or the Kawai Novus NV10. There are people who use these hybrids as just a MIDI keyboard and then generate the sound on a PC running a VST, like Pianoteq. I think this latter is what you actually mean since your example of a YDP-162 is not a "MIDI Controller."

I really like the keyboard action of my Yamaha P-515. I have no trouble at all moving between it and my teacher's Steinway grand.

I guess I wasn't clear enough, sorry about that. Yes to a keyboard that is just a controller, with everything else being done by external computer, speakers etc. At the moment my YDP-162 is indeed just used in that sense, as a controller. Thanks for the recommendation on the Kawai.

Thanks for the reply!

Just purchased a Yamaha P-515 today. It was about $1800 with all the stands, pedals, and such. The action is called NWX and it felt great at the store. Not too heavy and not too light. I personally like heavier keys in digitals. I also played a Yamaha CP-88 today, which had a NW-GH action, and I was impressed. This goes for $2500+. I own a Yamaha G3 and have played on various Steinways, so the Yamaha CP-88 in my experience is something you should try along with the Yamaha P-515. I'm sure there are other brands to look at too such as Kawai, Roland, etc.

Perhaps worth noting that the P-515 has the same keyboard as the Clavinova CLP-645, which you may find easier to try out in a store. In my part of the world far more piano stores stock the Clavinova than the P-515.

If you are willing to accept something like the P-515 as a MIDI keyboard even though it has a sound generator, then something to also consider is the Kawai MP11SE which has a sound generator but no speakers. It has a noticeably lighter keyboard action than the Kawai VPC1, and also the action feels more authentic to me.

Your Yamaha Arius has no after touch.

I don't think Pianoteq supports after touch in any way. (And I can't think what that way would even be.)

So is after touch really a requirement?

Where did you get this information? Pianoteq's website says it supports polyphonic aftertouch which is especially necessary for clavichords.

Off the top of my head.

Alright, it's used for clavihords then. Makes sense, actually.

Acoiustic pianos have no aftertouch ... not in the sense of the word as it's used in electronic instruments. Anyway, digital pianos generally don't support aftertouch. (Does yours?)

In the world of acoustic pianos the term aftertouch means something entirely different.

You are probably right. But I believe one that does support aftertouch is the Yamaha Avantgrand - at least I've seen mention of this on this forum for the N1X.

There are techno-keyboards that support aftertouch. But those have no pretense of emulating acoustic pianos.
Indeed, the aftertouch is a means to control VIs that support aftertouch ... such as purely synthetic instruments, or electronic versions of instruments that need an element of control beyond note-on/note-off, like a violin.

Is that aftertouch for the pianos though, or for some other sample?
Many of the samples that evolved out of AWM use aftertouch.

No, this is a misunderstanding. The AvantGrands don't have aftertouch either - not as this term is used for electronic keyboards (Wikipedia: "Aftertouch, or pressure sensitivity - the amount of pressure on a key, once already held down").

What the AvantGrands do is, that they re-purpose the aftertouch MIDI message (since it is not used for it's original purpose of pressure sensing) to send information about the key release. But this is a proprietary solution and has nothing to do with actual aftertouch.

JoBert beat me to it.

Great minds think alike - so did I.

Although I was unable to play one first, I have played the action in other instruments. It was down to choosing between this and the Kawai ES8, which I did get to play and really liked. (Honestly I would have been be happy with either.) I guess I am generally a Yamaha action guy, I still play my 35 yr. old KX88 controller every day, and will probably continue to do so.
Anyway, the furniture stand is backordered until late June but I negotiated a nice stand to hold me over that I can keep. I briefly considered the white version bundle, which is in stock, but my wife didn't like the look. Since she gave me no grief about buying another keyboard (with 8 or 9 already set up in the basement), I acquiesced. Happy wife, happy life.

According to UPS tracking, it may be here (Long Island) by tomorrow (Friday)! That seems improbable - but I am stoked.

So then I guess the question is: which aftertouch did the OP want? My mind immediately went to the definition of pressure after the key has been pressed, used mainly in synth-type sounds since the OP was talking about a MIDI controller.

But I'm also confused by the OP's request for something to practice piano on after hours, but then requesting a controller only. Most controllers do not have piano actions, but synth actions to accommodate non-piano sounds.

I own a controller that has no sounds and it has a synth action - the Nektar Impact LX88, but for silent practice on piano, I use the Kawai MP11. The MP11 works great as a controller, but since it is a piano action, it's not the best to play string sounds or organ. If you're looking for a piano-only controller (with no pitch bend or mod wheel) then the Kawai VPC1 is perfect for that.

Your LX88 may be semi-weighted, but there are plenty of 88 key controllers with piano actions. . . the Kawai VPC-1, Studiologic SL88 Grand, Studiologic SL88 Stage, NI Komplete Kontrol S88, Arturia KeyLab 88, Akai MPK Road 88, the very affordable M-Audio Hammer 88, etc., etc.