Hmm, maybe it's just me but the Grab-N-Go kit doesn't look that impressive. So for $30 you get a cheap backpack with a few very basic (and cheap - as in not so great quality) items. No tools of any kind, no flashlight, no way to start a fire etc. I'm not really sure how you could upgrade that kit. It might be better to avoid it altogether and save your money. Even the generic pocket survival tin that costs about the same looks pretty good compared to what you get with this package. Another $5 will buy the plastic rain poncho and a lot more bottled water than is included in the Walmart kit.

I understand buying a commercial kit may be convenient for some people. But all in all, you could do a much better job assembling a survival kit from scratch. It might cost a little more (or maybe not) but in any case it gives you the freedom to tailor the contents of the kit to your specific needs. Also, most commercial kits on the market contain items of substandard quality, oftentimes so bad they pretty much fall apart the first time you try to use them. YMMV.