Please note - I'm not a Real Estate pro. I'm a Buyer, Landlord, and investor here in PA. I am also a successful sales professional. So my commentary and thoughts will be as an educated consumer whose been buying selling houses with their own money for quite some time.
Connie - your profile lists you as "buyer and seller". But clearly this particular question is the Seller half of you. So ... as a Seller what do you really care about? May I assume it's, "Selling your house for the best price possible and in a timely fashion"? Right?
If that's correct, then look at it this way - open houses are merely one of many "tools in the tool chest". Are they effective? The "simple" and short answer is yes. BUT - they are a very minor part of the marketing plan. Whether they work 1% of the time or 5% of the time, they have *SOME* effectiveness.
And this is going to be affected by What Area the home is in. Big time! In certain urban areas, they would just be an excuse for noisy neighbors to come waltzing through your home to see it, whether they are qualified or not. In a more suburban setting, they have - in my personal opinion - more validity.
The open houses that are truly effective and that you SHOULD have - are "Realtor/Agent Open Houses". These are open houses that are ONLY open to real estate professionals. This gives your home a lot of exposure to many agents/Realtors. I think that it's important to do one of these at the very start of your listing. Why? Are all these agents supposed to know how REALLY LOVELY your home, merely from a few photos on the MLS and Internet? Yeah I didn't think so. So it's important to get all these agents to KNOW your home. So if you have done YOUR JOB correctly as the Seller (making sure it's Staged and Priced Correctly), then ALL those agents become your potential pool for bringing buyers to you.
There has been an "interesting" sidebar discussion here on your thread. My thoughts are the following:
1. Dual Agency is not illegal in PA. It is allowed here but not in some states.
2. Dual Agency is not "Unethical". That is a ridiculous notion, in my personal opinion.
While Dual Agency is certainly not unethical, Agents can ACT in an unethical manner - if they did not properly and accurately disclose to both parties how dual agency works. You know what? Any agent can be "unethical". That's right - even a dedicated Buyers Agent or Sellers Agent. So this brings me to my next point, or rather - right back to the very start of the whole thing.
You want to SELL your home for the most money, in a timely fashion, right? Some things you need to do yourself, like stage your home and get it really prepped, de-cluttered and cleaned spotless. An agent can help with some advice but it's your house at the end of the day. You also need to make sure that you are priced well, against proper current Comps. Your agent can help with this quite a bit and you can also do some research here on Trulia.
The other thing you can do is get yourself a super good, highly successful and super experienced Selling Agent. Your home is one of the largest investments that you have. So, you need the best representation that you can get. I would recommend that you interview several very successful agents, to find the right one for you. You may have to interview at least 3-4, perhaps even more.
As a Seller I think it's Very Important to focus on agents with a Solid and Proven Track Record, year over year. Why? Because I'm a sales professional and I can tell you from my experience that the people who consistently do a lot of business ARE DOING THE RIGHT THINGS. Period. The results do matter! Of course, it is also important that you can have a good relationship with your agent - certainly!
There has been some acrimonious discussion on your thread, which I think is unnecessary. It's regrettable that one person chose to hijack your thread and make it into a personal soapbox. But, perhaps this is somewhat useful as it indicates a fair bit about that person and who they are, right? I'll leave it at that.
I hope that you found this helpful, and appreciate a "non-pro" jumping in here to provide my thoughts as well. I hope that you have found some value in this perspective.
Lastly, you are certainly aware of Earned Income Tax here in PA. But please do be aware that the rate does vary by area (some areas have none). The official PA site for this is: http://munstatspa.dced.state.pa.us/Registers.aspx.
So ... if you buy in one town vs. another you might save yourself thousands of dollars per year in taxes.