I'm going to guess you're not a Digitrax fan. That's fine, and I'll admit Digitrax isn't my favorite either. Yes, I could have sunk another $40 bucks into this and put a TCS T-series or something else that fits a 9 pin straight plug in there too... but fact is I have a pile of perfectly functional Digitrax decoders sitting around surplus since I upgraded other installs, they're already bought and paid for, so why not use one of them. If for whatever spurious reason this one lets the magic smoke out, fine, I'll take the shell off, unplug it, plug another spare decoder in, and I'm on my way again lather rinse repeat until I've run out of Digitrax spares, at which point I'll probably be in a nursing home and this will be someone else's project.
If I had wanted to pay huge money on this, I would have just gotten a Rapido and been done with it. Instead I bought a 20 year old model off eBay, did a basically zero cost upgrade to DCC, and I'm using the money saved to do things like add some detail parts including twelve LEDs at three bucks apiece into it. All told, I don't think I'll have $100 in it when I'm all done. But I will have a decent RDC model.