I use Trupanion and have no complaints so far. I would get the insurance as soon as you can before you have any problems with the pup, otherwise anything that comes up before you have insurance will be on file and will be considered pre existing conditions and will not be covered in the future.
I actually ended up canceling my insurance once my dogs were prelimed. It just wasn't worth the money. I think putting the money I would spend on insurance away in a market fund or like savings account is actually better. JMO.
Thanks Elisabeth everyone is intitled to their own opinion however I am not financially well off and if something extreamly expensive did come up like emergency surgery for example I may not be able to pay up front at that moment then I am in trouble either need to give up my dog or have him put to sleep and just don't want to take that chance.