OK, here is what I got...understand these are tort/insurance guys and trial lawyers so they have their biases..
None of them would touch immigration law. They just saw it as "beneath them"...also said that the earnings are not really there, because the higher dollar clients are not there. However they admitted that it woul;d be pretty easy to be your own boss as an immigration lawyer.
As far as tax law, they said you'll always be able to make money, but to really bill high numbers, get a CPA as well. (yawn!) Tax laws is best suited to work within a firm acording to them. Also, tax laweyrs don't spend a lot of time trying cases.
They also said that tax law provides many government opportunities to make policy or review things before they become law.
They told me that a lot of younger guys are doing really well with bankruptcy law, which gives you a chance to learn about business as well as a lot of courtroom time.
Something to consider. Hope it helps.