There are several:
As I see it, the only drawback to using a springfeed vs. a stock class feed is loading speed/complexity; it takes a few more seconds to load a springfeed. However I am developing products that will cut down the steps and potential errors involved in springfeed loading - stay tuned and subscribe for updates!
After several tests I have determined that all of my parts are tough enough to withstand the rigors of paintball. The mounts have survived multiple direct hits at point blank range, as did the mounting rings. The delicate parts (i.e. the M1 sight apertures) will definitely break if hit directly, but I provide spares for those.
I stand by my designs and my products. If your parts break, please use the contact form and get in touch and I will make it right. I only ask that you take pictures of the damage so I can see exactly how the break occurred - it helps with R&D.
The mounting dimensions for the SpringPheed are unique to the Phantom platform; however if your marker is a Nelson style tube with a 1" diameter body and 7/8" diameter barrel, you can get it to work. The mount will need to be affixed to the body either by drilling/tapping the body for a 8-32 screw hole or using some kind of fastener (velcro strapping, zip ties, etc).
I am currently developing SpringPheeds that will work on Autocockers/Snipers and Automags (utilizing the Empire springfeed adapter insert) and also have plans for a universal SpringPheed system that simply clamps onto the barrel and indexes onto the breech. Subscribe using the toolbar at the bottom of the page for updates!
I also offer custom work! Take a lot of pictures and measurements, or if you prefer, send you barrel and body in to me and I will mock up the design for you. All custom projects must be discussed with me beforehand using the contact form.
The Generation 1 SpringPheed requires extra milling and thus is available only on a special order basis. If you must have one, contact me I'll send you a quote with the expected lead time (they will need to be custom made then finished with the subsequent batch of tubes). Cost will be $90 + shipping.
I initially offered low mounts but decided to discontinue this after the first run. They were a hassle to make, requiring grinding down the standard length screws, and the truth is the aesthetic difference between standard and low was unnoticeable without calipers - the difference is less than the width of a dime. Additionally, the thinness of the plastic around the mounting screw is a potential failure point; this wasn't an issue with Gen 1s because they were anchored through the aluminum tube, but with Gen 2s and newer, they are anchored through the plastic mount. I haven't had any reports of breakage here, but I'd rather have this area thicker than too thin.
Please see my Troubleshooting page.