personal injury lawyer，这样收费有何利弊？要签约了，肯请好心人帮

personal injury lawyer，这样收费有何利弊？要签约了，肯请好心人帮忙！
25% of any gross sum obtained in settlement or trial award. In addition thereto, the atttorneys are to receive all costs and di*****ursements, including but not limited to, investigation expenses,expense for experts or other testimony or evidence, filing and service fees, and costs for stenographers and notes of testimony, expended by them in pursuit of any settlement or suit.