This is all true to my understanding as well. Also they decide church by church (mostly) what rules to follow, so there isn't some Amish pope decreeing things they all have to do to stay Amish.

Some examples I've been told/seen:

• use of washing machines was allowed because it saved hours of drudge labor, but they were all in one communal location so that everyone still had to get together to use them. Dryers were not allowed

• one telephone was allowed in the community for mostly emergency use, but individuals weren't allowed to have phones in their houses because it was feared they would spend their time talking in isolation instead of gathering as a community

• pneumatic/air powered tools were allowed, but not electric or gas powered. No idea how they were running their compressors though

• one community didn't have enough water rights to farm all their fields for like 3 years in a row, so when the power company approached them to build a small solar farm they jumped at the chance to gain some use from the field they weren't likely going to be able to farm any time soon. The community had no electricity other than a street light at the end of their drive where it met the paved road. It was kind of funny watching them drive horse and buggy around a solar farm right next to their big old timey barn

• forbidding the consumption of tobacco (and lots of other vices) but they grew it to sell outside of their community as a cash crop

I think the comparison to the ultra orthodox is pretty spot on, I met a guy that said he would ride in a car but only if someone else opened the door for him. He also had a neighbor that would come over and turn on his electric lights when he needed, but he felt ok turning them off again without intervention.

Different sect but a fun Mennonite story: I saw a big family of Mennonites all dressed up in an airport terminal waiting on a flight to Las Vegas. The oldest man was eating a corn dog