I am not an expert in all of this so check all advice freely given.
A Sole Tradership can be very cost effective.
It is very useful for single professionals working alone.
Sole Traderships can inclue one or two employees under their umbralla.
They are great for firms of one or two people and/or for people who run businesses from their homes.
Yearly accounting returns are less onerous but you would be welll-advised to still have accounts done professionally by an independent chartered surveyor.
You are pretty well completely exposed in terms of liability and fiduciary responsibility.
You need good professional indemnity or other insurances to protect you from catastrophic losses/claims.
Partnerships used be very popular amongst professionals.
They allowed a greatly increased workload to be addressed.
They allowed pooling of resources and sharing of adminstration costs
They allowed collegiate companionship and instant mutual advice and assistance.
However, setting one up properly still needed careful consideration.
The problems with Partnerships is always the other partners
There are issues relation to fair distribution of workload, monitoring and control
What are the duties of the ther partners, what do they bring to the table?
How are the profits [you should be so lucky] to be divided?
What mechanism is available to call another partner to task?
Unless its set up as a limited company other competent, law abiding Partners can end up being personally liable for one errant other partner's malpractice or crimes.
Unless you have a formally set up Partnership Agreement, you may find you're not a Partner at all!
And as a professional in an unlimited company, you may have significant liabilities to third parties as well as fiduciary responsibility to members of the public.
You are even more exposed in terms of liability and fiduciary responsibility than a sole trader, and as the projects may be larger and more costly, so the claims arising may well be significantly larger, even on a pro-rata basis.
You need lots of good professional indemnity or other insurances to protect you from catastrophic losses/claims.
So partnerships have fallen out a favour in recent years.
That leaves the Limited Company.
These are no longer the "trade badly and walk away" deals of yore.
Nor can you go around running up debts, paying them with the VAT, winding up the company and starting up a new one.
There are also significantly higher duties of care for Directors and Shadow Directors.
Just preparing the accounts, advertising and holding the AGM in a compliant manner can demand significant time and energy.
But the company tax and the limited liability sweetens the pill.
But hold on a moment - this is like the Eddie Hobbs line "you cannot benefit from the equity built up in your home unless you sell it and live in a tent."
You cannot rely on the limited liability clause except as a shareholder. Directors who trade fraudulently of incompetently may still be liable under the law.
And availing of the limited liability is only done at a time of collapse, when assets are not sufficient to cover debts, liabilities or claims.
You should visit the website of the Office of the Director of Corporate Enforcement at
http://www.odce.ie/ and learn about the roles and responsibilities of Directors, Shadow Directors, Company Secretaries, Shareholders and the like.
Be aware also that, as an employer and a director, you are obliged to know about
- employment law,
- safety, health and welfare at work law and
- all laws that apply to carrying out your business in whatever country/jurisdiction you trade in.
One piece of free advice you would do well to take is to ensure one of you is a damned good organiser/project manager/time management expert.
Another might be that you should "test the water" amongst yourselves before setting anything up formally.
You might do this perhaps by going on a focus group weekend with a Facilitator [or whatever they're called now] to express your ideas about the business venture and communicate them to each other, to assess each others strengths and weaknesses, particularly in the areas of communication and co-operation
You should do this to make sure each of you share the same ideas in terms of understanding what the proposed business venture is about, each persons responsibilities in the structure of the firm, your own personal aims and ambitions and to initially outline a projected "five year plan" if you have not done so already.
You'd be surprised how many ventures fail to establish these basic yardsticks.
Not everything can just come together like a teenage rock band.
That's enough to think about for now.