As both Trent and Gary said, the MRC Advanced Squared has solved some of the problems of not reading back CV's from a programming track, although there's no doubt that MRC has the most difficult time reading back CV's from some sound decoders without a booster. However, the Advanced Squared is a quite a leap in price beyond the basic MRC, Digitrax, and NCE starter sets. Since I think we're sticking to entry level type sets, the Advanced Squared is hard to justify. OTOH, I've never had a problem reading back a CV on my Digitrax Zephyr and never heard of a problem from the guys that use the NCE Powercab. Reading back CV's may sound like mumbo-jumbo right now but it's really vital once you get up and running. You can program a change in a speed setting, for example, and have the CV read back to confirm that the setting took. If you don't get a read back, you have to put the engine back on the main to see if the setting worked. Even then, you're not sure if the setting didn't take or you just entered the wrong setting. Believe me, this will get old really fast.
The Dynamis really needs the Dynamis Pro to be able to have all the functions of the basic Digitrax and NCE sets, which takes it way above the entry level price point. The infrared remotes use a bidirectional signal, which makes it fairly reliable even in brght light, but the lack of ability to read CV's on a programming track for the standard Dynamis puts it out of the running for me, even if the price point was lower.
This really leaves us with the NEC Power Cab and the Digitrax Zephyr in the running for entry level systems that will do most of the things that are really important. Both are easily expandable, have radio wireless throttles available, can interface with a computer to allow remote programming of CV's, and will program and readback CV's on a programming track. The NCE uses the contoller as a handheld with the wires leading back to the transformer. The Zephyr has a more traditional powerpack arrangement, with power being supplied by a wall wart. It also has two Jump ports, which allow good quality DC power packs to be used as additional throttles, so you don't lose your investment if you already have some decent DC powerpacks. The Loconet buffer is unique and allows easier computer control than the NCE models.
The NCE Powercab supplies 1.7 amps. The Digitrax Zephyr supplies 2.5 amps. For most home layouts, you'll never need the additional power but you will notice the difference if you start adding stationary decoders or run more than two or three sound equipped locomotives. Both have boosters at reasonable prices that will add all the power you'll ever need.
The front runners are both great systems but with quite different form factors. I like just setting the trains in motion and not having to find a place to set down the controller. Others like to have the handheld controller because they like the immediate access to the controls without having to walk back to the control station. I strongly recommend that you try both systems in person before deciding what to buy. You may really like one and hate the other but you won't know without some hands on experience. Don't be overly swayed by any of our experiences, since some of us have developed a love for a particular system second only to our wives and kids, and you know how things go if you say something bad about them.
Either one will do what you need to run a nice DCC layout but it's really no different than buying a car without a test drive. Nothing replaces hands on experience.
