According to studies, bicalutamide appears safer, more convenient and more effective than flutamide.
http://www.ncbi.nlm.nih.gov/pubmed/16845534"There are no direct comparisons between the three non-steroidal antiandrogens in terms of quality of life, but available evidence suggests that bicalutamide has a more favorable safety and tolerability profile than nilutamide and flutamide."
Urology. 1996 Jan;47(1A Suppl):70-9; discussion 80-4.
Worldwide activity and safety of bicalutamide: a summary review."Bicalutamide is a new antiandrogen that offers the convenience of once-daily administration, demonstrated activity in prostate cancer, and an excellent safety profile. Because it is effective and offers better tolerability than flutamide, bicalutamide represents a valid first choice for antiandrogen therapy in combination with castration for the treatment of patients with advanced prostate cancer."
http://www.ncbi.nlm.nih.gov/pubmed/10587288"Three non-steroidal anti-androgens are available in the US, i.e. flutamide (Eulexin), bicalutamide (Casodex) and nilutamide (Nilandron). Nilutamide offers patients no benefit over flutamide or bicalutamide and has the least favorable safety profile. Because of its short half-life, flutamide must be administered 3 times a day. Furthermore, flutamide therapy is associated with a relatively high incidence of diarrhea, often intolerable for some patients. Bicalutamide is available in a convenient one tablet, once-a-day dosing regimen, is at least as effective as flutamide and is better tolerated in terms of diarrhea."
Arch Ital Urol Androl. 1999 Dec;71(5):293-302.
Antiandrogens: a summary review of pharmacodynamic properties and tolerability in prostate cancer therapy. "As regard as pure antiandrogens clinically important adverse events including gastrointestinal events, particularly diarrhea and occasional disturbances of liver function related to flutamide treatment and antabuse effect, problems with light-dark adaptation and rare interstitial pneumonitis related to nilutamide indicates the bicalutamide, due to its better tolerability profile, together with its once-daily oral administration regimen, could be considered the antiandrogen of first choice in the treatment of prostatic cancer."