With so many astrology systems available in software form, the first decision isn't which product to buy — it's which system you actually want to study. Vedic astrology, Lal Kitab, KP and Numerology all answer similar questions in different ways, and the software built for each reflects that.
Start with the system, not the software
If you were trained in one system, or a mentor recommended one, start there rather than switching based on software features alone. A well-built tool for a system you don't yet understand won't teach you the system — you'll still need to study the underlying method.
Free trials and demo versions matter
Before buying a paid edition, use a demo or free/earlier edition where available. It tells you far more about whether the workflow suits you than a feature list does.