I'm not a BB expert, I just watched my first season ever (BB2) for the first time last month, so I'll only speak to that season and I'll just let you know the few things that stood out to me.

1) Skip BB1, from what I've read the first season is extremely different from the rest of the seasons (moreso than Borneo vs. other Survivor seasons) and they changed up the format a lot and it had bad reviews at the time. It's best to start with Big Brother 2.

2) There are a lot more episodes in a season of BB than Survivor. Like, you cannot blast through a season in a week like you can with Survivor. There's something like 30 40-minute episodes. It took a looong time to watch.

3) That being said, you definitely get more invested in the characters and wrapped up in their world. Although sometimes it's frustrating to have episodes where effectively nothing happens. Because it's not a nomination or an elimination, so you're kind of just watching the highlights of people in a house. I think you could get away with skipping those.

Bottom line: If you like Survivor because of the strategy/characters/social aspect/unpredictability then all those reasons make BB2 worth a watch.

If you like the ~unpredictability~ of Survivor, which is one of my favorite parts of Survivor - the fact that anything can really happen, that anyone could go home, or even win, then BB2 is definitely worth a watch. Because it is edited as it is filmed and airs even the editors don't know who wins, so that makes it a lot more exciting (to me) that literally anything could happen, there's no Kellys who have no chance of winning because of their edits.

Hopefully someone who has watched the more recent seasons can give a better idea of how BB has changed since the earlier seasons.