Eduardo,
As you noticed I said "dive a lot" and you said "dive at most once a month". If you’re going to be diving at most once a month that means you probably won’t dive the cold months -Oct through March at least- so you’re looking at diving 6 times a year. In that case I would say that set up is great for you. Something that avoids renting gear, and as you said allows you to go out if the urge strikes.
I made 114 dives last year, and will make between 150-200 dives this year and I dive all 12 months of the year. Higher end BC vests will usually have more, and better quality (metal vs plastic) attachment points, as well as being more comfortable, etc.
Higher end regulator sets will breath easier in general, and have the ability to adjust the airflow as you dive which makes breathing easier as you dive deeper if you have an interest in that. In my case, almost all my dive in the last couple of months have been 80 deeper.