Not many realize that, but Production division is the only division that encourages true marksmanship. It penalizes hosers really bad... If you want to learn how to shoot you need to learn how to excel with Production gun.
Well......despite what many may think about certain IPSC divisions (ahem...Open...), you can't really win in if you don't shoot the points. All things being equal, at the upper levels in any division it ALWAYS comes down to the points.
To the OP:
My advice is; as soon as you can, start hanging out at IPSC matches or league nights and asking a lot of questions. Ask people why they shoot what they shoot, what are the pluses and minuses, and what's necessary and what isn't. Most IPSC shooters are gear whores in varying degrees and will be only too happy to let you test-drive their guns and gear and explain in micro-detail why they made these specific choices. Take every opportunity to familiarize yourself as best you can with the different platforms available to you before you decide on a platform and/or division. With a large enough sample you will be able to boil your choices down to a very short list.
Since the question is on the table I'll offer my suggestion but know that I'm just another opinion, of many. So for what it's worth:
If you start out in Production Division with a CZ variant you will be well served. Glocks and M&P's are also fine but if at some point you want to really compete you will be swimming up hill with the heavier triggers. They are great guns, durable as hell and reliable, but any way you slice it an 8 lb trigger is going to be a lot harder to shoot fast accurately than a 2 lb trigger. It's just a fact. Also, if you start out in Classic Division with a 1911 variant (in 9mm) you will be well served. There are plenty of affordable choices out there. Leave Standard and Open for later consideration as those divisions are big money pits. Ask me how I know this....
Re. the safety: If your gun has an external safety in Standard, or Open Division it must be applied after the load and make ready command. If it is a Classic Division gun it will have external safeties by definition so they must be applied. If you are using an approved gun with external safeties in Production Division, the hammer must be double action for the first shot and an external safety will be redundant in this case so it is not required. Glocks and M&P's do not have external safeties and can play in Production, Standard and Open Divisions. 1911's can play in Standard, Open and Classic but not in Production due to the single action trigger.
All of the internet warriors on these forums can give you all the advice in the world and some of it may be very helpful depending on what it is and who it comes from, but if you don't try before you buy you are just asking to spend money in the wrong direction.
Good luck with your choice and welcome to the family.