The choice of the legal form will always depend on your individual situation and many factors have to be taken into account.
The major aspect would be the risk you are willing to take when running your business. You have to be aware that as a sole trader your liability will be much greater comparing to a limited company and your personal assets may be in danger.
If you are not based in Ireland you will not be able to register as a sole trader. The other trading option available to you would be a limited company. In this case directors do not have to be based in Ireland.
Trading as a limited company gives more business credibility. It may be easier for the company to obtain finance and to enter into business relationships with other traders. Limited companies are seen as more reliable and trustworthy.
The decision to incorporate will also depend on your previous trading history. It makes sense to make the transition from a sole trader to a limited company once your trading income is stable and you have an established clients base. This gives a greater chance of success for your new company.