Personally I would get it with the thumb safety. It's all personal preference.
Then you can carry it with a round in the chamber.
If you don't want to use the safety, you don't have to, but it'll be there if you do want it.
If you buy the model without it you can't have it installed later. it's an all or nothing design.
Also, if you ever decide to sell it, it'll increase the sales audience.