"Soft" lights are OK. Not the best, but sometimes the clear ones are hard to find.
You want to avoid the "Reveal" or "Clear-Sight" type bulbs, those are the ones that seem
bright to us but are dark to beardies.
For a basking lamp, I much prefer a Halogen Spotlight or Floodlight. (Lowes, Home Depot, etc)
They are WAY less expensive than those "basking" lamps from the pet store, and do a better job imo.
I started with a 100 watt "basking" lamp (which was still a bit too cool -- around 98 F) but now
I use a 75 watt Halogen Floodlight for the basking area and that still requires me to dim it about 10-15%
to stay at 107 F.