I would stick with the Dex, If that's what it had from the factory then I'd keep using it.
I heard somewhere if you use traditional coolant instead of dex it could wear away at seals and cause more harm down the road.
Chances are the reason your coolant feels sticky is because someone mixed regular coolant in with it. From what I found mixing them can cause it to gum up or become more gel like.
ALSO from what I found online It looks like if you flush the ENTIRE system and then just go with the good old 50/50 mix of the green stuff then you should be okay. Personally I would flush the hell out of it and then refill with the Dexcool.
Do some research or maybe call a dealer and see what they say about it.