my experience from being a popsical subscriber + android tv + my own amp($200) + cheap wireless mic (foc with amp purchase) + sm58 ($100? cant rembr):
pros
1. easy to use
2. app support
3. local support
4. songs db are relatively up-to-date
5. cloud access means u don't have to constantly update a local song database
6. songs currently not available can be requested, tho no promises that it will always be made available but at least there is an avenue for song requests
cons:
1. quality of songs is hit-and-miss. some are professionally edited to remove vocals, some are just some muffled background noises which are not even in-sync with the lyrics. these can be few-and-far in between, depending on what song genre u usually sing
2. some features can be improved, like a personalised / fav song list or smth. maybe there already is, but i just cant seem to find it
for $9.9/mth i think its not too bad, but i'm always exploring to see what better options are available. hope this helps those who are on the fence.
i see alot people who are posting here asking for help on how to setup and wire up your systems. everyone has your own unique k and amp systems, those who need help with wiring your systems, do take the initiative to post more pics(ie. the back connector panel), share details like amp model number or link to website with the specifications, and see how the community here can help. where i have the time aside from caretaking my 2 kids, perhaps i can help out here too.
From youtube reviews the 100 is even better in some ways to the 300. 
