I have the 50w and I can concur with others that it is more than loud enough for single use. There is a power selector knob that has .5, 20&, 50w settings and I mostly play at the .5 level and occasionally 20w. I have a small practice room and at the 50w level it is way too much especially if you have single coil pickups or a hollow/semi hollow guitar you may experience some horrible feedback.

However if you can work around all that there is one discernible difference between the two models that might interest you.  The 100 watt amp gives you 8 presets versus the 4 that comes on the 50. This may or may not be a consideration for you unless you’re really into custom tones you’ve either created or downloaded. 
Just something else to think about. For me I use both acoustic and electric for this amp and I can change modes from acoustic clean or country twang or high rock distortion with just a push of a button. 

Moe