Do 5-pole DIN tonearm connectors deteriorate the sound?

Yes, the BMC is balanced.  So too are my Atma-sphere MP1 and my 3160 Phonolinepreamp.  In my Sound Lab system, everything is balanced, front to back. Nearly all current driven phono stages are balanced, but not all; the Sutherland Loco appears not to be balanced. (There are 3 Sutherland current driven stages; at least one of them offers RCA inputs only and is said not to be balanced.)  Since the most common way to do current drive (BMC excepted) seems to involve an op amp, and those can usually be driven in balanced mode, I have to wonder whether Sutherland drives what is really a balanced current to voltage gain stage in SE mode, in order not to scare away customers who are used to SE phono operation.

I doubt there is a "right choice". Each choice of the two has its advantages and disadvantages. I do not change wires for different types of cartridges, as does Dover, so I personally do not benefit much from a DIN connection. In my case, I just haven’t had the time or urge to bypass the DIN in the tonearms I own that do use it. I do tend to mount my very lowest output LOMC cartridges in those two of my tonearms (Reed and Triplanar) that have continuous wiring from cartridge pins to phono stage, in the belief that there ought to be a benefit. Since we are being anal, why not a balanced connection? But you’d need a balanced phono stage to take full advantage of balanced wiring. Also, there is the silver vs copper conundrum.

Reed and Triplanar can also be purchased optionally with straight cartridge to phono wiring, as were both of mine, to name only two of several other than Schroeder.

In theory, one would think that any connector is worth eliminating when possible, and I have two tonearms with direct wiring from cartridge to phono stage, but in the case of other tonearms I also own and use and that do use the DIN connector, I cannot honestly say I hear any "problem", when I have compared the SQ of the very same cartridges in the very same audio systems, mine that is, comparing straight through connection to DIN connection. Is it possible that there is the tiniest loss of fine detail? Yes, but as connectors go, I think the Cardas DIN connector, if you’re using both male and female halves, is a very good one.

I read the referenced section on the Origin Live website regarding solder joints vs DIN connections, and I have no beef with that, but I do wonder at the concerns related to resistance of the wiring. In many phono stages, especially but not only tube phono stages, a resistor is deliberately inserted in series with the signal, right after the phono input. This is usually to prevent oscillation of the first amplification device and in tube units is typically 100 ohms or so. So why be concerned about a few ohms of resistance in the wire when the signal is going to encounter a much larger in magnitude series resistance inside the phono stage, before any amplification or RIAA filtering?