Just went through this last month with one of my dogs. We opted for the tightrope over the TPLO. Long story short, my dog had an underlying problem that was not properly diagnosed, and she ended up dying due to complications after surgery. We talked with a number of vets, and the consensus was it is a toss up between the two methods. One prefered the TPLO, the other the tightrope. Either way they will never be 100% again. If the TPLO goes south (i.e. bone infection), you're really screwed, and since its quite an invasive surgery its a real possibility. The tightrope is much less invasive, and if something goes wrong, its not nearly as messy. Also, I'm sure your vet probably told you, but the torn CCL could be just part of it, the meniscus could also be damaged/torn... My dog was older 8yo, but in good shape and not overweight. There is usually an underlying issue that causes the tear, when one goes, there is something like a 70% the other will go as well. In my case it was arthritis which deteriorated the tendons.
The thing we were stressed on was to make sure to get them rehabbed as soon as possible so they don't lose muscle mass, it prolongs the healing and takes forever to build back up. It can be the difference of 3-4 months post surgery to a year and a half... The sit and wait game can be very detrimental to their long term success. If the dog is not using its leg, the muscles will atrophy very quickly. i would certainly talk to other vets and get a second and third opinion.
Best of luck, hope your pup heals fast.