Hi Michelle and welcome!
Molly (Terri Lynn) is right...this is a very subjective question. You will get answers all over the map on this one!
It really does depend on what you are looking for. For instance, if you want a less expensive dog, F1 is the first consideration, multigen the last...but if you go further and want other traits, most often involving coat quality, the higher the generation, the more likely you are to get what is referred to as low-non shedding or low-non allergenic. Now, keep in mind, please, that no dog is completly non shedding or non allergenic...but the more Poodle (and sometimes other dogs) in the mix, the more likely you will get the coat that Labradoodles are known for.
F1 dogs have great personalities and, in my opinion, are among the most healthy. Why? Because when you breed two DIFFERENT breeds, you are more likely to bypass some of the genetic problems in each breed.
But, sometimes you get dogs that can have the same genetic disposition and in Labradoodles, one of the most troublesome is hip dysplasia...so, (especially if you are looking at F1 and F1B dogs) you need to carefully select the breeder to be sure that he/she is testing the breeding stock before allowing the dogs to breed.
I hope that this helps...there is so much more to consider, but I think that this is a good start.
You are doing a good job to research this issue...I suggest that you continue to research until you feel confident that you understand what to look for in a breeder and in your puppy...we are here to help, so, please ask!