I tend to do thing in bullet points, so here goes:
--Hypogonadal means clinically low testosterone. However, you have to realize that those number are actually VERY low. One of the big labs defines hypogonadism at about 350 and below now.
--Primary means that your testes are not producing enough testosterone. Your brain responds (pituitary) by pumping out more LH/FSH in order to try to compensate.
--I shouldn't have used the word rare, but it is much less common on this board for whatever reason.
--I really can't advise you on medications. You've got to do your own research and discuss with good docs. I will just say that HRT, at least, has a lot of studies showing its safety in the short and short medium term. It's looking about as safe as one could hope for, but no one knows about decades of use of course. To me it seems like it would be safe due to the fact you are simply restoring hormone levels using a bioidentical hormone to natural levels (unlike steroid users). However, none of us has a crystal ball.
--AIs are pretty safe as far as drugs go, but they are synthetic and pharmaceuticals, so I think it is naive to think they will not have any effects. Also, these sometimes have short term side effects that can be difficult. FightLowT, for example, hated Clomid and felt like it hammered him emotionally.
--Imo your doctor should do his part and you should do your part. If you have an existing medical, then you want to find a good doc that can diagnose and treat you partly. The thing to realize is this though: many disease can now reversed, partially or completely if you go naturally: diabetes, arteriosclerosis, etc. But this is a very involved subject.
--Testosterone may be a silver bullet for you. However, most men have more than one issue going on. And I can't emphasize enough that even if your lifestyle is not good, testosterone may help you in the short term. But eventually a poor lifestlye will catch up to you.
Now you may have been a health freak all your life and in great shape except for the testosterone. But that is usually not the case. So just realize that artifically raising your hormones won't clear out your arteries, protect you from the ravages of stress, fill your body with proper nutrients, etc. So do a lot of reading over the next few months and learn what is missing in your life.