Well, I would recommend BULATS, since that's what we sell
But actually, there are quite a few issues with TOEIC. It is basically a multiple choice listening and reading test (reading and listening are the easiest to test thru a computer medium).
I have heard the scores are not that reliable, especially at higher levels.
WIth BULATS, you can test all four skills + grammar/vocab, and the computer test is adaptive so the candidate can't just get lucky by guessing the mutliple choice answers. BULATS is more British, of course, it's a Cambridge test, and personally, I feel the oral and writing tests are the most useful. sections.