Hope things are going well for you in Perth. Ricki is right about many different answers.
I choose a mechanical valve becasue I was 38 and the thought of doing the surgery three more times was not something I wanted to do. I have had no side effects from the warfarin. I manage the drug according to my diet and lifestyle. I still eat green vegetables and I drink in moderation. I am an avid hiker, biker and I train with weights. Other than bruising a little easier when I stub a toe or hit something it is no big deal. As for feeling better I knew when I woke up in the recovery room that I was better...no joke.
I am almost three months out and feel fine and am better than I was before. Good luck.
Welcome to HVJ. I'm sure you'll find a lot of support and answers to your questions here.
I had my aortic valve replaced this past May. I chose a bovine valve specifically so I wouldn't need to be on blood thinners the rest of my life. On the other hand, some people choose not to get tissue valves because they want something that probably will last the rest of their lives and being on blood thinners isn't that big a deal for them. The bottom line is there's no right or wrong answer and each valve has its trade-offs.
As for feeling tired, I was VERY tired all the time before my surgery. After surgery it took some time, but I now have no energy issues. For me, cardiac rehab made a big difference in regaining my energy and strength.