Why Do Modern Players Use "Negative Doubles" In Bridge
The short answer is - use whatever your partner and you are comfortable with using.

The long answer is - the penalty double at the one or two levels rarely works out the way you think.  Either their partner will switch to a different suit (where you may not want to double for penalties again), they will SOS redouble for takeout (again to a suit that you may not want to double), or they will play in the doubled contract.  You'll find they'll make this contract a maddening percentage of the time, or only be off one.  The times that you have the strength to set them a large number at such a small contract, you could have bid game or slam yourself and make at least as much, if not a lot more.

This is why people really don't penalty double at the low levels anymore.  In competitive auctions, it's much more useful to use the double to find a fit.