We got the 6000. It's on sale right now for 250. Had it for about 5 years now. We never had any mold problems but we're in a fairly dry area. The beanbag will come with a removable cover that you can just toss in the washer to clean on a normal cycle. I take it to a laundromat so that I can use the big dryer because it's a lot of fabric. It'll fit two adults no problem.

Maintenance wise, the biggest hassle is fluffing it on occasion. Ours is massive, so it's almost a two person job to move it around so that the foam resettles and you get a cushier feeling. Smaller ones are probably easier to reset. Once you sit in it for a while it molds to your form but it is still fairly adjustable. I give mine a few sharp kicks to remold the seat if I don't feel like doing any heavy lifting that day. It's cathartic.

It is very comfortable. All that being said, it's a right pain to get up once you're settled in. It's not great for people with mobility issues. Sleeping on it can be uncomfortable. If all that sounds good to you, then ultimate sack is a good value. Just as good as love sac but far less expensive.