The programer who is willing to do it on his own CMS he is asking a 30% share of the business and he said he will look after the website for all the time... is not that a good deal? probably not.
That's for you to decide. I know nothing about your business model, costs, projected turnover, etc. If you're giving away 30% of your business, I'd get legal advice. If I recall, owning at least 26% of a business makes you an equal partner in that business, so be sure you're happy to give that power to someone. Is the 30% in lieu of direct payment? If so, what incentive is there for them to work on it with no guarantee they'll even get paid or get paid well? They could get half way through the build and decide it's not worth their time if they doubt the integrity of the business. 30% of nothing is nothing.
It all sounds a bit too risky to me, but then again I'm getting an outsider's view of the situation.
Are you wordpress programmer or you can write your own CMS as well? I'm asking this because - people who tend to be wordpress programmer always say that wordpress is best, but those who write their own, they say wordpress is crap.
So Im looking for someone who is expert in both and his saying is some kind of a golden point not just very subjective.
Also would appreciate if other programmers would post some kind of reply.
I know what you mean, I see a lot of people promote Wordpress for every type of site when often it's not the best choice.
Do you think you need a custom CMS? Did you consider this before the developer mentioned it? Why do they feel you should pay them to develop one for you?
You may find you need a custom CMS but this should come from research and a thought-out business plan. Write a checklist of what you need the site to do and look at open source and premium CMSs out there to find one that does what you need it to do. If you can't find one, you might be better having a custom one created, but most existing CMSs out there can be modified to do exactly what you want if you have a developer who knows what they're doing.
I've heard too many stories about developers biting off more than they can chew and vanishing with payment, or a businesses paying a hell of a lot more than they expected to because the custom system doesn't work as well as they'd expected.
If I was you I'd stick with a tried and tested CMS (at least for the time being) that A) you know you can get support for, and B) has millions of users who can vouch for its speed and stability.