Who is the best for companies: a tax accountant or a normal accountant?

both are required

tax accounting is for the purpose of calculating tax amount .this benefit will goes to govt.this accounting for governement purpose..but in the case of companies tax acccountant can give advice or opinions to company that how to reduce tax amount,so company would save huge amount by the help of expert tax accountant

The company should have the services it needs within a relevant effective cost taking in consideration the risks and other disadvantages.
To make a long story short, some small companies might hire many full time regular accountants & make specialists handle the taxation part based on contracts.

I think as a junior accountant in External Office & have some Accounting & Taxes Activities i preffer the normal accountant with some course for sales tax trick or action or planing .
  thanks, Chihadeh Qamhawi

both required but tax accountants is a speciality