⭐⭐⭐⭐ because I have had it for about a month, but it was a targeted purchase for me (600Ah start), so it immediately did the job for which I bought it.
During the period from its first full charge until today, it has started the motorcycle battery three times and the level of stored energy is at 4/4 (three starts - one month and some standby).
I consider it a worthy machine at a reasonable price.
Because there is a reason for the existence of comments regarding guidance for purchases targeting specific "tasks" such as battery start, I will come back with a comment after six months to tell you about quality, results, endurance of stored energy, and capabilities of the Jump Starter TM-18B.

21/01/21
I come back a year later for an obviously more detailed opinion.
Excellent machine indeed, after days of inactivity in both the car and motorcycle, whether in hot months or days with excessive cold, while there was no chance of "getting started," with this particular machine, everything worked satisfactorily.