MacVector has a very cool BLAST Map results tab that displays the annotations surrounding any hits from the selected database. Particularly if you are working with prokaryotic sequences, where most BLAST hits these days are to genome sequences. This can really help you see the context of your hits, and let you download just the relevant region for additional analysis.
A few years ago the NCBI introduced a “throttling” procedure such that unregistered users are limited to three requests per second per IP address. While most users may not see a major difference with this, if you are sharing an institutional IP address with other MacVector users, you may find that the BLAST Map tab is slow to populate, and other NCBI-related functions may also be slow. You can get around this by registering for your own personal NCBI API key. Once you have a key, you can register it in MacVector using the MacVector | Preferences | Internet tab and pasting your API key into the Entrez Server edit box;
Once activated, your key will enable MacVector to submit up to 10 requests per second irrespective of other users at your Institution, which will dramatically speed up population of the BLAST Map tab and other NCBI services, particularly in shared environments.