VISA TYPE B-1 Business Visitor
ADVANTAGES
Quick. Decision to issue B-1 Visa made by U.S. Consulate upon application at Consulate.
Documentation is simple — letter from U.S. trainers returns to home country.
DISADVANTAGES
Compensation by U.S. trainer is NOT permitted.
Reimbursement by U.S. trainer for reasonable out-of-pocket expenses is allowed.
Does not work well if:
 • training program will last more than several months;
 • trainee is not already employed abroad; and
 • trainee is single and young (meaning, without strong ties to his/her home country).
Most risky of all options because authority to issue B-1 Visa for training is vested in the U.S. Consular Officer abroad who makes the final decision "on the spot." If trainee is eligible for Visa Waiver Program - see Comments - then decision to admit the trainee is vested in U.S. Immigration Officer.
COMMENTS
If trainee is from one of 28 countries for which B-1 visas are not required, may enter USA as a "WB" under visa waiver program (but stay is limited to 90 days). 
 
VISA TYPE H-3 Trainee
ADVANTAGES
Allows trainee to be compensated by EMPLOYER.
DISADVANTAGES
Requires U.S. trainer to file a petition with the CIS. Trainee applies for visa at U.S. Consulate upon petition approval.
Time for petition preparation, CIS decision, and issuance of Visa varies, but often takes 10-12 weeks.
Petition must prove existence of structured training program in which trainee will not engage in productive employment. (Trainee must be a fifth wheel.)
On-the-job training without a classroom-type training can cause CIS to deny petition.
COMMENTS
Limited to a maximum period of 24 months.
Key is existence of a specific training program that advances trainee through various stages of U.S. trainer's business.
Must provide CIS with a detailed training program plan - not just a summary outline.
 
VISA TYPE J-1 Trainee (already working)
ADVANTAGES
No CIS involvement.
U.S. trainer can compensate trainee.
DISADVANTAGES
Trainee might be subject to the two-year home country requirement that precludes the trainee from acquiring H-1B, L-1, or "Green Card" status in the USA until the trainee has spent two years in his or her country of residence for two years after completion of the U.S. training program (there are some exceptions).
COMMENTS
Limited to a maximum of 18 months.