Ever since the iPhone was released with its proprietary headset jack, people have been looking for ways to use their existing headsets with their iPhones.A majority of complaints stemmed from the fact that people may have invested a lot of money in higher end headsets and no longer could use them anymore. One of the first companies to provide a solution was Belkin, but the Belkin adapter just allowed you to use your existing headset with your iPhone. The product I am reviewing today basically lets you use your existing headset and provides microphone functionality.
Enter the Monster iSoniTalk. Luckily, I got this as a gift, but I think that if I needed to buy an adapter/microphone combination, I would buy this device in an instant for a number of reasons.
First off, as a Monster product you can be sure that the product is a first-class product. As always, monster uses high quality materials such as gold contacts and Duraflex to strengthen the microphone cable.
Secondly, it seems as if Monster actually took the effort to engineer the product with the consumer in mind. I found that the "cable management" system (clips to hold your headset cord that were placed strategically along the microphone cord) really helped and the clip on the back of the microphone also came in handy.
In any case, if you are looking to replace Apple's standard OEM iPhone headset with your aftermarket headphones, then have a look at the Monster iSoniTalk. You will essentially be getting two products in one, a headset adapter and a hands-free microphone.
Pros:
* Allows you to use your existing headset
* Able to answer incoming calls without taking off your headset
* Backed by a 1-year limited replacement warranty and the "Monster" name
Cons:
* At times, wires may seem clumsy and get in the way
* May make you wish you had a bluetooth headset
* Price may be an issue as Monster products are usually expensive.

I have had the iSoniTalk for several months now. When it works, it is fantastic. Being able to use my noise-canceling headphones for phone calls is great. I also love the ability to be hands free. I often make calls from my iPhone instead of my landline just in order to use my iSoniTalk setup.
But there are two downsides. First off, the length of cable from the plug to the mic is over 2 feet shorter than my headphone cable. This may be a function of the nice length on the headphone cable and not the other way around, but it's annoying regardless.
The biggest issue is something that has cropped up recently. The plug's connection with the iPhone is faulty. When I am on a call or listening to music, it will drop the right audio channel until I apply pressure on the top of the plug or twist it around. It feels like I'm adjusting rabbit ears on my TV.
In using other connections, like the standard Apple headset, I know it's not an issue with my iPhone.
My next step is to track down Monster and see about getting a replacement. Hopefully it's just an anomaly and not a design flaw.