I'm looking to set up powerline ethernet in my vacation home. My office is upstairs; the wireless router is downstairs, and the response time is horrible when I'm working.

Any thoughts, recommendations, etc. that I should know about before making the investment?

You've got nothing to lose. Just buy a pair of adapters and see how they work.

I've got 4 powerline adapters in my home, and they work great.

Try www.bearextender.com for a good WiFi extender. Only $45

Waste of money. Believe me, I've tried all kinds of wifi extenders, from Linksys $150 extenders to Hawkings, etc. None of them worked reliably as powerline.

The absolute best repeater I ever used was a pair of Netgear WG102 access points in bridge mode. Threw the signal solidly and reliably 300 yards.

Cheap on eBay.

I use the netgear HDX101 adaptors, they were LISTED as HD adaptors about three years ago. I think in my tests, they do about 90mbs, which is enough for me to transport HD around the house and a LOT of data and video streaming. They can be found onine, but I buy them from ebay for about 25$ a piece. Key to using and expanind adaptor usage IMHO is STAYING with one brand and type. I know there are standards, but i find that enough staying within a same spec and switching brands causes slowdowns and security issues (these adaptors will allow a password for access to data)

That said, I have been using the technology for about seven years now without problems and great ease of transport

Are you suggesting that the adapters be the same brand as the router, or just the same brand as each other (i.e. all adapters should be Netgear HDX101, etc.)

Any issues when the plugs are on two separate circuits? The router is in the living room; I'm hoping to run to my office upstairs.

I suggest the ADAPTORS be the same, not necessarilly as the router. I have linksys and apple routers and dlink, but these are netgreat powerline adaptors. I haven't had the problem of cross circuit traffic, I HEAR that doesn't work well - or AT ALL though.

Would your house really be on TWO CIRCUITS? this is pretty unusual,

OK... circuit breakers, maybe...

If there is one line coming into the house, and you mean two different circuits after the breaker box there should be no problem at all in using a powerline adapter.

if you mean your house has two separate circuits coming in and half the house is on one and half the house is on the other, which would be strange unless you had one heck of a vacation home, that would not work, they would need to be on the same main coming in.

You may have to try different ones in case one is on one hot wire and the other plug is on the other hot wire (most houses have two "hot" wires coming in with about half the house on one and half the house on the others, for the ethernet adapters to work their best they should both be on the same hot wire), but there's a 50/50 shot of getting that right.

I would definitely suggest going with the latest standard - HomePlug AV - that offers faster throughput and will work better in a variety of home wiring environments.

I'm using adapters from Plaster Networks that I would REALLY recommend because of technology they have added on top of HomePlug AV. In my experience, their adapters are pretty much bullet-proof. They work great!

The Apple Airport Express is rather good for this purpose as well. It plays very nicely with a number of brands of WAPs, supports WPA (some wireless extenders don't), and adds iTunes music streaming to the equation.

It's also very teeny tiny!

I LOVE the AE, but I have noticed that it will NOT do WDS without a lot of work and that is only with TWO router types. I use it with my other Apple Airport products, but I was only able to get it to do WDS with an ASUS router (and that was just one, not the whole router range)

So, if the OP is looking for distribution, the AE would be great hanging off something like homeplug, but to get it to distribute one would be best served only in conjunction with other apple router products