HerbalAire, or Da Buddha, and not just because I own, and love them both.
Don't get me wrong, I love my Solo, especially after getting a brand new one in the mail yesterday, thanks to my unit still being under warranty.
What would steer me away from it in this specific case is that you mentioned that they "like to have a lot of people around", and I have found the Solo sessions I have had with even three people to be a little lacking. I find you need to really hold onto the Solo for a bit and milk it with some slow, steady sips in order to get to where you want to be, and this is obviously not conducive to a group setting.
The HerbalAire is a great unit, it has the added perk of doing bags, and as mentioned it is very much an all-in-one package. You won't be needing any bits and baubles, or accessories for it for a long time. I've had mine for over a year, and while I admittedly only
really use it in bag mode when friends are over, I still haven't even used all of the bags that came with the thing
.
I have never heard of anyone being disappointed with a 7th Floor Product (Da Buddha, LSV, or Silver Surfer). Consider ordering a blemished Da Buddha unit straight from 7th Floor
themselves. Keep in mind, this means that the unit will have a small dent, scratch, or chip. Mine has a small scratch on the top of the housing, but I assume the main reason it didn't pass quality control is because it is a little wobbly. Fear not: the unit is hefty and it isn't going anywhere. In spite of these units being "blemished" they still have the same 3 year warranty as a new unit would, and mine honestly makes my HerbalAire look like a cheap piece of plastic when they are sitting on the same surface (which I no longer allow). Sadly, it cannot do bags, and it might be a little less party friendly, but I would say that it was overall a better investment. Considering that it uses convection verus conduction, this means that you are not wasting herb while it sits in a hot steel bowl, and the all-glass flavour is hitting in a league above the metallic (plus plastic if using bags) taste of the HerbalAire.
Truth be told, you'd be happy with all three, although I would worry about not being able to savour the Solo fully if it is being passed around too much, as mentioned. I would also suggest the E-Nano on hearsay alone, as I have no personal experience with that unit. The Underdog is also a beautiful unit which is very similar to the E-Nano. I would also ideally suggest perhaps taking a look at the Pax, or the Plenty, but I feel that both of those would probably be out of your budget, although you didn't put a hard cap on it as far as I can tell
.