I've done a side by side photo of the RT Pen and the original Weller.
When about the half wattage is enough, much table-space and cash can be saved with RT Pen. The RT Pen includes every feature for hobbyist usage.
I've tested the the RT Pen with the new GaNFast power supply from AUKEY (PA-Y21) with 30 Watts. Worked fine, and is even smaller and more lightweight than the used from ARTSYN power supply.
Here are some photos of the comparison: