KJ, I bought an iTroll in 2013 and used it a little over 200 hrs, trouble free. I would recommend the iTroll. I chose not to get the hunt feature but understand that feature is nice. Good luck in your choice.
Here's a link to an old topic I remembered reading. Enter downrigger cable in the search box and you may find more topics as well. I put 150 lb power pro on one of my semi manual riggers and haven't experienced the cable hum.
http://www.lakeontariounited.com/fishing-hunting/topic/49978-anyone-using-powerpro/?hl=%2Bdownrigger+%2Bcable
Here's an old post that may help you.
http://www.lakeontariounited.com/fishing-hunting/topic/48895-pro-troll-black-box-boat-voltage-signature/?hl=%2Bpro+%2Btroll+%2Bblack+%2Bbox+%2Bvoltage+%2Bsignature
Can anyone give me a vote of confidence on using Shop Epal.com for marine electronics. The majority of the reviews I read are okay but a few reviews were less than acceptable. Thanks
Dawson, did you check ebay.
http://www.ebay.com/sch/i.html?_from=R40&_trksid=p2050601.m570.l1313.TR0.TRC0.H0&_nkw=+stock%2Fforend+for+a+20+gauge+870&_sacat=0
Catatonk Paul, I'll post a link that may help you on the information your looking for. You can click on the word Forum near the top left hand corner of the page for a host of information. The Marco Island area is under the ten thousand island region reports.
http://www.floridasportsman.com/regions/10000-islands/