I've got a RA2 setup with more than 100 devices. It's very reliable, as reliable as my old RA1 setup was. Yes, with more than 100 devices you need a second main repeater. The repeaters combine to make a network that supports up to 200 devices. They're programmed using the same software, it's just a matter of a software license key that handles supporting the 2nd main repeater (and thus +100 devices). Note, there some physical devices like keypads and repeaters consume more than one of the 100/200 device counts. So if you're close to 100 or 200 in physical devices then you really need to check.
There are some additional scene features in what they call this 'Inclusive' level of the software. One that sure seem like they ought to be in the 1st tier, but that's a whole other discussion. I'm very pleased with the configuration options thus far.
If you want conditional programming (if/then/else) then you either have to use Homeworks QS or a 3rd party controller (either embedded or PC-based). Conditionals are nice in that you can have things being triggers based on a variety of factors. I plan on using 'something' to handle this. I'm debating Elk vs HAI and haven't yet decided. I'll have to play with each of their programming tools to narrow down which better suits my interests. Again, that's another discussion...
I think the only thing I would like to have in RA2 would be the ability to have the dimmers change their default level based on time of day (or ambient lighting). But I think that will stop being an issue once we get to the point where we find a 'sweet spot' on the dimmer levels. Haven't gotten there yet as we're still unpacking and haven't even BEGUN to start decorating.
Window treatments, furniture and other decor elements all come into play where lighting is concerned.
My advice is treat the wiring like it wasn't going to be automated at all. That way you can fall back to that come resale time, or when technologies change. That and think carefully about just how irritating an automation system can be when people have expectations of 'normal' light switches. I'm finding it's best to have the room's 'main lighting' on a regular paddle-style switch and not on a keypad. This way anyone coming into the room isn't faced with having to make decisions about buttons one the keypad when all they need is LIGHT.
That and placement of keypads is helped by there being a hybrid unit, one that has buttons AND a dimmer built-in. This way that single-gang switch position still serves it's duty for a 'switch' but then also has buttons for other functions. This becomes important when you've got large rooms that serve multiple purposes. We've a combined ktichen/family room/breakfast table arrangement that needs keypads at each to handle overlapping lighting control. As in, being able to bring up one area while dimming another, or turning 'everything' off. The hybrid makes it easy to swap one in later, in place of a regular dimmer, when you discover you really did need more keypad control... But, again, make sure the 'main lighting' still has a paddle switch.
I found it invaluable to have a lighting consultant come out from a local lighting place. We went through during the rough framing stage and rearranged/added/subtracted a few things based on the consultant's insights into lighting. I'd strongly encourage anyone doing a 'gut job' to considering doing the same.
