It depends on how much karaoke you are doing and how seriously you take it.
I have had an Essential Karaoke Twinology for years, basically the same thing, in fact probably exactly the same thing but rebadged.
Gary's point about a high quality lead is well made. It DOES count. Doesn't have to be amazing, just not the B-Tech red & white leads or the type that come thrown in with a cd player for free.
What you will find though is that if you own legal discs the cost of a real karaoke machine starts to become minimal in comparison to the cost of the disc library. Real machines have a lot more facilities, read faster and put fewer strange black blotches on the screen.
If all you are doing is buying the Bassline 6 pack for parties and offering it to people without really pushing karaoke, it is a fine option.
What I found was that because I was not a frustrated singer pretending to be a karaoke host, people started to enjoy the karaoke and started wanting more. Then I had to treat it more professionally and buy a proper machine. (A Soundlab! One of the few Soundlab products I own! Eeek!).
One thing I found about the Twinology. It doesn't get on well with cheap radio mikes.
It introduces an amazing amount of interference to the cheap "throwaway" radio mikes I handed out to singers. The Numark CDN25+G doesn't do that, nor does any other real karaoke machine.
There is a lot more to the anti-shock thing than most people realise. Contacting the tech support of various companies does NOT yield thorough answers as their staff are not properly briefed on this aspect of their machines.
Eventually all this anti-shock/digital out/twinology compatibility business was explained to me by someone not involved in the disco field. The disco manufacturers buy in chipsets from Chinese companies. The Chinese companies are very dynamic and will change where they licence the chipset designs from in a heartbeat.
This means that anti-shock/digital out/twinology compatibility can vary not just from machine to machine but even from production run to production run. No one really knows what is going on.
In short if you have an anti-shock machine, test it with the converter. That's the best advice I can give.
I still say it would be a great idea to have a machine that has anti-shock that does not strip out the subcode that Gary is talking about (possible and some Numark and Skytec machines at least), AND that has digital out WITH DSP effects (like the Denon machines). Technically, this IS possible, but no single machine that I have come across does it.
Of course this is far too good an idea to actually ever happen!