In the long run, it is better to start with full Y-genome testing for genealogical purposes, instead of putting money into the panels.You get SNP testing (haplogroups), Y-STRs andfull mtDNA in one test. Taken individually, they would cost much more than a single full Y-genome test.
For less than $600, Y Prime from Full Genomes Corporation (FGC) will test and report over 400 Y-STRs. FTDNA's Big Y tests a similar number, but they are not reported. However, either FGS or YFull will analyze the BAM file (available from FTDNA's customer service) and report them for $49-50. It is thus much more likely that a branch-defining Y-STR will be found than with the panels.
But, more importantly, they test over 10 million base pairs for SNPs and private SNPs (point mutations). Their average mutation rate is about 1 in every 3 generations per 10 million base pairs. Thus, there is a good chance that the test will uncover private mutations that occurred in the last 400 years. They would be conclusive proof that a person belonged to the branches defined by them, since SNP parallel mutations are only rarely found in humans.