I have the modmic and can attest to it's very good build and mic quality. The shitty thing about it is the very long and cheap feeling cable. Do you want a mic that attaches to the headphones, or would you also be OK with an option like a Olympus ME-15
No but you're usually better off buying the microphone separately if you want good quality audio. An exception would be the Sennheiser PC350/360 or similar. They aren't cheap either. At least not as cheap as Grado SR60i plus a ~~$10 clip-on microphone~~ $25 clip-on microphone.
Pretty cool stuff but if he wants to take it to the next level there's some equipment he could invest in.
Top of the list and often overlooked is a good microphone, audio quality is just as important as visual if not more. I can stand a 480p video with good audio more than a 1080p video with tinny and windy audio.
Something as simple as this and plug it into an audio recorder in your pocket, then in post line it up with the video.
Or if you'd prefer to record the audio straight onto your video camera this should do the trick on a budget.
And for voice-over segments, there's plenty of choices on amazon. Any mic in the 30-50 quid range should def do a better job than the current one.
It'll instantly increase the production value
For the GoPro Mic http://havecamerawilltravel.com/photographer/gopro-external-microphones This is the thing, if you plan on uploading A LOT of Vlogs (more than 6 per month) you should invest in a better camera. The fish-eye on the GoPro enables you to take some really cool shots, but it gets annoying if it is used over and over again (at least thats my opinion) plus with the GoPro you will most definitely need a "selfie stick". Tried to Vlog myself using the GoPro Hero 3+ and either half of the screen was covered by the arm I was holding the camera with or my wrist would start hurting. (I suck at doing this stuff LOL)
MY BEST ADVICE would be to use your phone. If you have a fairly recent phone, of a fairly high-end brand, it should be able to record at 1080p 60fps no problem.
This YouTuber recorded his entire trip to Japan with his G4. He was recording for extensive periods at 4k... in japan... during summer... the sensor kinda overheat and you can see some distortions in the image quality every now and then.
If you want better audio, you could use your phone and buy one of those mics that you attach to your shirt and then swap the two audio files.
A mic like this: http://www.amazon.com/Olympus-145045-ME-15-Microphone/dp/B000815CF4
Im pretty sure you can even find them Bluetooth. So it really goes down to personal preference. Hope Ive been of some help :)
http://www.amazon.com/Olympus-145045-ME-15-Microphone/dp/B000815CF4
This is something i found on amazon.
Or a small mic with a shirt clip, so its much closer to your mouth. Much easier setup.
http://www.amazon.com/Olympus-145045-ME-15-Microphone/dp/B000815CF4
PS - Mechanical or spring keyboards are seriously over-valued by some. They're back in vogue because they're rare. But there is a reason they disappeared to begin with (they were loud, slow to type on, and expensive).