So I just called the help line and here is what I found out...probably what you guys already knew and were trying to relay to me. Options: Chip: easiest to plug and play. CD Rom: Good because you can put the maps on your computer, then look at the maps on a big screen. you can also then download a few maps onto your device so you don't have to change chips out. Also...I think he said you may not have to "activate" the whole maps on your unit so it may not take up as much space and may help it run faster? Can put it on multiple computers...but he told me it will only work with one device, which goes against what some have said...don't know who to believe on that one. Down fall...have to order and wait for it. Download: Instant map that you get immidiately. The guy said that you can only download one map onto a SD card at a time, and that if you do mulitlple map downloads, they jsut write over eachother. For example. Lets say I wanted both the Mn Lakemaster and the WI lakemaster downloads. If I did the MN one first, as soon as I downloaded the WI maps it would in essence erase the MN maps. I really questioned him on this because I didn't think that seemed right...but thats what he said. So I asked him if...once I have put the CDs on my computer and loaded them onto my SD card if I could run multiple maps at once. He said that you CANNOT have two maps running at the same time. For example...if I bought the city Navigator maps to see local streets and the Lakemaster chip for the lake that I would have to "engage" the street maps when I am driving to the lake, and when I got to the lake I would then have to "disingage" the street map and then "engage" the lakemaster maps. So it seemed like best options would be either getting the CD or getting the chip. Honestly...I may call back to double check with another person. I can't believe that if you downloaded the MN lakemaster maps, then downloaded the WI maps you would lose the MN maps.