From my experience and I have done a course which went from Rescue to MSDT in Thailand these are the Pro's and Con's
Pro's
1. get to meet lots of very interesting people, from many different cultures.
2. possible to assist on 5 dives a day, thats 3 possible courses a day,
3. have the choice of every course to assist on, you will rarely find a day where a rescue, OW, confined water, advanced, DSD or tour was not happening,
4. assist in the day to day running of a very large diving school with up 100 divers per day.
5. live eat and breath diving,
you are at a school, the trainees usually hang out with each other, and talk diving, and diving, and more diving. Around you are other students, OW, advanced, they are also in the cafes close to the dive school reading their books before an exam.
Cons
1. stay at home and meet a few people from your home town and the occasional tourist.
2. stay at home and assist every weekend, but only if the weathers good.
3. three weeks later you are still on the same OW course finally finishing this weekend yeeha.
4. not all schools operate the same, researching the school and the area should be a must do.
5. stay at home and try and study for your IDC with lifes distractions.
this was a typical week for myself during my DM training.
Monday.........2 morning dives Advanced course Afternoon.....assisting Rescue
Tuesday..2 morning dives/advanced course Afternoon/assisting Rescue Evening Night Dive
Wednesday...Confined 1 & 2 Pool Afternoon assisting Rescue
Thursday......Confined 3 & 4 Afternoon assisting final day of rescue Evening Night dive assist
Friday..........OW Afternoon Mapping project Ist Dive Free dive 2nd dive
Saturday.......OW Afternoon Advanced two dives Evening Night dive assist
Sunday.........Confined 1 & 2 Afternoon DM Skill test
Now I did this for a period of nearly eight months. Sometimes I had to go for my visa run, and of course there was time out for my Idc and IE. During the period I was doing over 100dives a month. And the majority of that was spent either assisting or teaching.
So please, before people want to put down Zero to Hero courses reflect on this timetable,
You eat sleep and breath diving,
at lunch you at talking about a course, answering a question, or asking one, all about diving.
At night you might be taking a bit of beer but you are still talking about diving.
It is all learning.
I am convinced some people just put it down cause they think you have to spend a whole year getting up 100 dives to have more experience, it doesn't make sense.
Yes I will agree that the training is done on a limited number of sites, roughly 15 where I was,
but knowing those sites well allowed for greater demonstration of my guiding skills.
I would encourage the OP to research his prospects well. Find out what you are not paying for, ie extra costs, is there a time limit, exactly what do you get for your money.
Weigh up adverse comments regarding the school with good ones.
If you are someone who lives normally in a colder than tropical climate, then try to ensure you are getting use to a different enviroment when you go home.