I own two GP35s and I think they are great. They are E-Z app locos, but I only use them with the Blunami app. The Blunami app is worth the price of admission by itself, which is amazingly free! The original E-Z App boards in the locos do not have the same capabilities as those of the newer Blunami boards from SoundTraxx or the BluerailDCC boards from Tam Valley. However, other than onboard sound, they are fabulous compared to DC-controlled locos. Unlike Bruette, I have extensive experience with my E-Z App locos. I have had them since they were first released, and they are my most used locos. For the most part, they are bullet proof. Occasionally, they don't respond as they should, and in most cases, it is probably because I did something stupid. All I do is either shut them down or remove them from the track and put them back on, and they always work fine. They are smooth runners, quiet, and will run starting from speed step two. I have some steep sections of track (+4%) and I never get tired of running them as a consist. It is very easy to do so and just as easy to unlink them. Speed matching is also easy and can be fine-tuned with ease. I mentioned that there is no onboard sound, and that is very disappointing. But what I do is use a Bluetooth speaker mounted inside a stock car and put it right behind the locos. It isn't perfect but does add a lot more realism than running a silent loco around the layout. I recently purchased a pair of Bluetooth speakers for less than nine dollars that are easily synced to have sound come from both at the same time. (My old speaker died from overuse.) If you want sound onboard, you will have to get the aforementioned boards from SoundTraxx, and I believe BluerailDCC boards may have onboard sound, but I'm not positive. If you get the newer SoundTraxx Blu-2200, there is basically no difference between using a loco with that board and the Blunami app and buying an entire DCC system. (Quick, duck, here comes the DCC guys.) Everyone has their preferences, and if you don't already have an investment in DCC, I think it is a no-brainer. The last thing I will say is you CANNOT use a controller that has pulse power. The loco will not work properly. I contacted Bachmann about inconsistent operation, and this is what they told me: "Any 16-volt DC system will work as long as it does not have pulse power on it it will work with the sound value engines." I retired my MRC TECH 2(?) and bought the MRC TECH 7. Since I got the new controller, I have had nearly flawless performance. Good luck with your decision. Glenn