I’ve read dozens of threads here and elsewhere, and I still have no idea what to buy when it comes to lighting controls. Z-wave or Insteon for dimmers? I don’t know how important instant status is or should be, don’t have a real sense of the difference in functionality and reliability of the various brands and can’t have light switches that look and operate differently all over my house. I have about 30 light switches in my house. Many are in two, three, or four gang boxes, and none are decora unfortunately. So I’m looking at a pretty significant expense ultimately. Even if I just get a few Z-wave switches to start, I’m going to have to spend the time to put in some dumb decora switches with them for WAF. Is a Cooper or Leviton switch really worth three or four times a GE/Jasco switch? Are the six-packs on e-bay a fools bargain? Right now the only Z-Wave devices I have are a couple of Schlage dead-bolts and a VeraLite which is still in the box because after I installed the deadbolts I read up and found I have to get replacements with newer firmware. I know I’m going to need at least a few light switches or something between them if I want them to both be seen by the Vera, but I’m really not looking forward to spending hundreds or thousands of bucks and all the time it will take to figure out the wiring and swap out switches and then have to trash them and start over later when I find they don’t do what I need.
Oh yeah - and what about wattage? Can I just add up the watts on every light bulb a switch controls? What about de-rating? How do you calculate four z-wave switches all in one box? Do you eventually get to zero?
Argh! Thanks! 
I’ll need your credit card number before I begin. But, I will offer you this…
If the effort required to learn and do is too much (it is a considerable effort) then hire a consultant/contractor to do the job for you. They’ll know what’s needed, be able to make recommendations, give you a total job cost up front and you’ll have someone to call/warranty/blame if it doesn’t work as promised. I guarantee you that it is the most cost effective way to go.
Your contractor might also tell you about in-wall micro switches like those from Fibaro and Aeon, that do not requite that you replace your existing switches.
Best of luck.
Its not that complicated. Take a breath and relax. 
;D
Dimmers vary widely on price. Some are cheaper because they are obsolete and being dumped (anything Intermatic, they exited the ZWave biz and someone bought all their inventory and is selling it off). I have used the Intermatic 6 pack receptacles and find they are great. I know once Intermatics are gone you won’t ever be able to buy more so either buy a few more than you need or live the possibility you may have to mix types later.
As for instant status that is application specific. If you are setting up an automation scene where the turning on of a device locally is to trigger something else to happen you’ll probably want instant status (or settle for up to a couple minutes before Vera knows the device changed state). If you don’t intend to do elaborate scene’s then you probably don’t care.
I used Leviton Vizia RF (VRI10-1LZ) dimmers ($45 on eBay). I liked the style and wanted the multi location dimming feature and they are available in 1000W in addition to 600W. This was important for a chandelier I have. I went with 1000W units everywhere as they were only $3-4 more than 600W. They were priced at $65 but I got them for less by buying 6 of them. The matching remote switch (allows multi location dimming of same fixture) was only $15 or so (VP00R-1LZ).
Many dimmers are only good for incandescent loads so be aware they may not work with dimmable CFL or LED bulbs. So maybe stock up on incandescent bulbs b4 they are banned (if ever).
I also used the matching Vizia RF on/off switch (non dimming) for up to 15A load (VRS15-1LZ ). It was insanely priced ($74.99) but I needed it for a 5 gang box to make them all look alike. I liked the Vizia here because it could switch a full 15A load whereas some on/off ZWave switches are derated to 600W max. I bought some Leviton 3 way Decoras on ebay to fill in the switches I’ll never move to ZWave. They were cheap. Of course new covers as well because I went from old style to decora cutouts. Cheap enough to not matter.
I have since bought one of the Aeon devices (DSC26103-ZWUS, $30 on ebay closeout) that converts a regular on/off switch to ZWave. The module fits inside the box and is controlled by the old switch. These are a good way to convert on/off only situation to ZWave control without changing style and look of switch location. You need some spare room in box so if it is a small box and chock full of wires it may not fit. I would use Aeon and a plain Decora switch instead of the rudely priced $75 on/off Vizia switch I used. Live and learn.
Aeon also makes a dimmer module in similar vein to the on/off switch but I haven’t used it so can’t say anything about it.
Anyway it is a bit of a journey of experimentation. Get started and add and refine your system as you move forward. No need to get it 100% for life correct in V0.1
Have fun with it.