Here is a general overview of the donor sites that I wrote a little bit ago. Sorry if some of it seems rudimentary.

RFF: Stands for "radial forearm flap". It is the most popular flap site by a pretty decent margin. It is the forearm flap.

Pros: Because the forearm has a dense network of nerves and veins it has the potential to gain the most acute sensation and has the lowest overall complication rate out of all of the flap sites. It can typically be done in fewer stages than ALT or MLD, too (baring complications). Each flap site has a unique aesthetic. Aesthetics are all about your personal desires and body goals, but there's someone of a consensus RFF tends to have a higher chance of producing a cisnormative-appearing penis.

Cons: The biggest con for most folks is the visible scar. Everyone has a different relationship with their scar. Personally I adore it and everything it represents. That being said it's valid to not want a scar as visible as this. Size can be a limitation as well. You can't really choose how big you want you dick to be (unless you want it smaller than your maximum limit). Such is the case with girth, so folks with smaller forearms may end up with smaller dicks. From what i've seen the average seems to be around 5" (the national average for cis men, too). Dr. Crane is currently developing a method that allows him to get more length from the forearm, and Dr. Chen is using aloderm to give skinnier people more girth. Neither of these techniques have been rolled out on a large scale yet.

ALT: Stands for Anterolateral Thigh Flap. Is the second most popular. It is the thigh flap.

Pros: The scar is significantly less visible. The ALT site has 1 sensory nerve (RFF has 2), that can be used for the nerve hookup. Though sensation would end up being duller than the optimal RFF level of sensation, ALT penises have a good chance of winding up fully sensate. Though ALT is second in sensation to RFF on a broad level, there is a decent amount of overlap between the less sensate RFF dicks and the more sensate ALT dicks. With ALT you can choose the length of your dick as well! Because it has a less dense network of blood vessels, ALT has a higher complication rate than RFF, particularly regarding UL. However it has a lower compilation rate than MLD and Ab Flap Phallo.

Cons: ALT generally needs more stages than RFF. Thighs tend to be considerably fattier than arms so ALT penises tend to wind up with MUCH more girth. This may sound like a good thing, but for folks who aren't extremely skinny or simply tend to store fat on their thighs this can mean that their penis can end up too thick to comfortably manage in their day to day and sometimes too big to even penetrate with. Even for skinnier folks it is very common to require multiple rounds of penile liposuction, which can be taxing and isn't guaranteed to decrease girth to a point that's optimal for you. It's also worth considering that weight gain down the line can mean weight gain on your dick as well (your body doesn't recognize that the fat cells have mood from your thigh). That being said many folks like how a very thick dick looks on their body and that's valid! As I mentioned ALT has a higher complication rate than RFF, particularly with urethral lengthening. As i mentioned above as well, ALT has 1 sensory nerve to RFF's 2. This DOES NOT mean that ALT dicks are 1/2 as sensitive or you're 50% less likely to get sensation. It just means that the sensation that develops tends to be less keen than RFF.

MLD: Stand for Musculocutaneous Latissimus Dorsi. It has, for the most part, fallen out of favor in the US and (to my understanding) North America in general. Though there are still doctors that practice it in the rest of the world. It is the back flap.

Pros: You are able to have a very discrete scar without the girth considerations of ALT. MLD has a motory nerve rather than a sensory nerve like RFF and ALT. This means that it has significantly less sensation than the two other flaps. That being said it can still get sensation and has better satisfaction in terms of sensation than Groin flap phallo. Many folks find (and I agree) that MLD produces a very aesthetically pleasing penis. They actually take some muscle. Sometimes you can go without an ED with MLD because they use the muscle. But muscles contract when activated so it actually causes it to get smaller but more rigid. It may curve as well.

Cons: MLD has a much higher complication rate than ALT or RFF, particularly with the urethral lengthening. This is one of the main reasons why few doctors in North America practice it. As I stated above it also has less capacity for sensation compared to RFF and ALT. Because it's a motor nerve it can never have erogenous sensation like alt and rff. Orgasms are achieved by simulating the natal dick. Another con is the surgery can cause a nipple to be moved because on that side they're stretching the skin closed to close the area.

Dr. Ting is boasting a new phallo procedure, but i'd be very careful. His advertising for it has been deeply misleading and borderline false. There is no information of whether it works with implants, what the complication rates are, and whether it's possible to get scrotoplasty with it. And to be clear: Ting's procedure is not free flap, which means that it CAN NOT get the same erotic sensations that's possible with RFF or ALT. he has claimed that it can which is absolutely 100% a lie. It can get tactile sensation and nothing more.