I went through the process last year with Dr. Bruce Chien (and I can't recommend him highly enough!).
1. How long it took: I can only say that it was way longer than it should have taken (many, many months after we submitted everything to the FAA instead of the 6-8 weeks that it should have taken in the past). From what I've read here and other places, it seems like everything is still backed up and taking much longer than it should. If you contact Dr. Chien or another AME who deals with lots of Special Issuance medicals you will be able to get a better estimate of what the current backlog is.
2. How complicated it was: I will say it was not at all complicated if you are working with the right advocate. I was given a very specific list of what tests I needed to have my cardiologist order and the order and timeframe to get it done in. There are certain tests and follow ups that have a 90-day window (or some other time frame--I just did what was recommended) and you may have to push your cardiologist a little bit to get the right tests with the right timing to satisfy the FAA.
3. Is it worth it: that really depends on the type of flying you do. I own a Twin Comanche and am in my 40's. I could have gone Sport Pilot as soon as I was recovered enough to self certify, but I really wanted to get some more traveling done in my twin. With the likely change to power factor that will hopefully be opening up some more aircraft to Sport Pilots at the end of 2023, it would be a harder decision if I was in my 60s or 70s. To start the clock with the FAA, you have to get the denial, and during those "weeks" (which may actually be closer to a year than a month), you have lost the ability to go the Sport Pilot route unless or until you have the SI granted, so that is definitely something to take into consideration. The best part about consulting with the right AME is that they will be able to advise you on whether or not you should even try in the first place.
Nota bene: pay special attention to what Dr. Bruce Chien (username: bbchien) has outlined above. If your cath report doesn't meet the under 70% requirement, it's time to go Sport Pilot. Don't let anyone submit anything for you until your AME can say that it is a slam dunk. (Also, if he's still taking new patients, hire Dr. Chien immediately and follow his advice to the letter. He doesn't charge nearly what he's worth and if he says to submit, you know it's the right decision so at least you won't have to worry about it as much while waiting forever for the FAA to issue.)