Wadia 861se vs All others.

Several great DAC's don't upsample. In addition to the Zanden you already mentioned, there is the (Kondo-San) Audio Note and 47 Labs. All three of these are great DAC'S.

Although I have not heard your Altis I seriously doubt it deserves being called garbage. Big gains in the world of CD come at very high cost. If you have good sound I would not worry about it.

I totally agree with Mr. Porter, many different technologies can offer reference level performance along with different "flavors" based on personnal taste and system synergy to provide great sonic pleasure. I audtioned many DACS, DCS,ML,Audio note and finally selected the new Ensemble DAC because it sounded the best to me in my system. There is no one "BEST" but many reference level DACS/TRANSPORTS that offer great sonics depending on what you like and how it matchs up with the rest of your gear.

Hmmmm....let's see there seem to be 2 issues here: (1) old vs. new technology & (2) up/oversampling vs. non-up/oversampling.

On the old vs. new technology I might be inclined to agree w/ your friend in that the CD chipsets have come a long way in a very short time & the cost is relatively low for these chipsets. IF implemented correctly, an inexpensive CDP is capable of very high performance for a very reasonable cost. Plus, the newer cheaper CDP might well rival an older hi-end CDP. Quite possible. So, older CDPs seem to be limited by the older chipset performance + the transport technology. Over on Audioasylum, Steve Nugent of Emperical was citing that a Costco Toshiba laptop had a really good DVD drive that could be used as a transport. This + a turbo-modded Benchmark DAC produced some superlative sound. I have no personal experience w/ this but I merely cite it as an example of a relatively cheap solution to redbook CD playback.
Re. (2): this seems to be a "religious" topic!! :-) there are 2 distinct camps & it seems that they are very polarized.
I think that it was incorrect of your friend to conclude that the dCS stuff bested his EAD gear just because of the high rate upsampling.
Your friend might like the sound of upsampled CDPs, which is an entirely diff thing & is just fine by all of us.

I can attest to the fact that my modded 47Labs Shigaraki DAC beat the Levinson 390S and Wadia 850 in my system. The diferences are not subtle and it does not over or up sample and has no filter on the output.

Your 8 year old Altis Ref and my 10 year old Audio Logic M-34 are BOTH extremely musically involving tube Dacs, period.
Don't believe everything you hear about up and over sampling being better because .............
Build quality is nice to have, but it is design engineering (power supply esp.) and execution with system synergy that reign supreme.
I know a lot of audio heads that would snap that Altis Ref. off the A-goN classifieds in a heart beat (if you ever decided to sell it)
Keep your Dac, it's very special.