What are the best treatments for lines above the lip or smoker's lines? Would you recommend microneedling or fillers?

These can be tough to adequately manage and you're going to find a lot of difference of opinion.  In some cases, we have found that if the lips are very thin, lip augmentation will help.  While not FDA approved, we have found micro droplet silicone injections to be very effective.  It has to be done in stages, but over many years, we have seen no significant problems.
Probably the most effective treatment, in my opinion, is CO2 laser resurfacing, and this is our major recommendation.  The treatment has to be quite intense and, on occasion, may need to be repeated.  I would mention that, in my opinion, micro fractional laser treatment is inadequate.
Fillers can be used for the deeper grooves, but the results are only temporary.  My preferred filler is Restylane.

Hi,
In my opinion, the best treatment for this area is actually a combination treatment.
You can soften overactive muscle activity contributing to the formation of these line by using a small amount of Botulinum toxin. Next step would be reducing the appearance of wrinkles, and here you can try laser or micro needling treatments. Both will help to induce the collagen, and some laser treatments can additionally "erase" some of the lines.
I keep dermal fillers as the last step if there are stubborn areas that need some fill-in. Usually, a softer HA dermal filler gel is used, and this can result in further smoothing of the lip lines. I do not advise use of Radiesse in this area.
Use of a clinical grade skin care with retinol and strict sun protection will ensure your results last longer and reduce chances of new wrinkles appearing over time.
I hope this helps answer your question.
Best wishes from Melbourne.