I started with Cooper's kits and would have no problem going back to them if, for some reason, I couldn't or wouldn't brew all grain any more.
I was amazed to find that I liked my home brewed Cooper's Original Series stout more than canned Guinness. The Cooper's Canadian Blonde Ale with 500gr DME and 700gr dextrose was a great summer beer.
Those were pretty basic recipes. There is plenty you can do to mod the kits: change the brew volume, swap the yeast, hop teas, dry hop, partial extract, mini-mash, add chocolate, add lactose, add spices, toucans...