There is talk about it but it's not really so much that the drinks themselves make you put on weight or stop losing. It's more that there's a theory that it could set off a sweet craving, making you more likely to eat other things that you otherwise wouldn't. Personally that's not the case, the total opposite in fact.
Personally, I don't agree with eat whatever you want as long as it's under your calorie goals. That's hardly healthy is it? Losing weight isn't just about getting the weight off, it's about being healthy and for that you need a well balanced diet. Otherwise you'll lose weight but you'll also lose muscle, your metabolism will be lowered and you'll generally look more flabby as you'll have a higher body fat percentage. I do think that a little of what you want and like, in moderation, as long as you're under goals is perfectly fine but whilst eating 1200 calories of twinkies a day might cause you to lose weight, it won't leave you a healthy individual at all.
If you like cherry coke, pepsi max have just released a cherry version. Personally it's a bit sweet for me but I know others who rave about it. I know they sell it in ASDA for £1 for a 2 litre bottle.