I would consider the NEL coils first myself. they are lighter , less expensive and the Coiltek warranty is written in such a way that they have an easy out :
1. How long is the warranty for my Coiltek product?
"At Coiltek Manufacturing(CTM) we provide a full 2 year warranty on all of our manufactured coils and accessories (some products may vary). This warranty starts from the date of purchase by the customer. This is applicable worldwide. This warranty covers any manufacturing errors like cracks in plastics or performance issues like no response which are from manufacturing faults – usually these are noticeable within the first few hours of use. The warranty does not cover normal use or misuse of the product.
For a coil/product to continue to perform well it must be treated with care and not be used in a way that will jar or incur any sudden impact. This sudden impact may result in developing a noisy product. CTM, at its sole discretion, will determine the nature of the returned item and decide whether it is a warranty issue. Each individual case will be reviewed on its own merits and the more information you can provide the easier it will be for us to make a quick decision."
On the CTX coils , they have to be sent to Australia to see if the company will honor the warranty or not. I think the 11" procoil is hard to beat but if you want a smaller , more nimble elliptical coil , the NELSharpshooter will amaze you--very difficult to go back to the procoil and much less weight and cost than the 5x10. If you're thinking bigger , the NEL Hunter is lighter and less expensive than the Coiltek 8 x 12 and $100 less and 1/4 pound lighter which is a lot when you're swinging it all day. NEL cords are on the verge of being TOO heavy weight and are a bit of an issue to slip through the shaft but the coils performance has never been disappointing.