Top positive review
Use over the ear style during running! Great Sound for bluetooth.
Reviewed in the United States on September 6, 2015
Disclaimer: I never had the jaybird bluebuds x so I can't compare it to that.
I purchased mine at bestbuy(to get a geeksquad warranty) about a few weeks ago and I'm very happy with it. Jaybirds has a lifetime sweatproof warranty. Here is my 2 cents:
Sound quality is great - As good as my $100 bose soundtrue earbuds(for a regular joe, it is more than enough). I use to watch movies on my mac and netflix on my roku and it sounds great.
Noise cancelling is passive(enough to zone in but safe enough to hear surroundings while running).
Battery life is as advertised - Ran for a week running 5-7 miles daily, watching movies without charging. Gets approximately 8 hours.
Connectivity - No issues except for old bluetooth devices. Disconnected once but it was my old 2009 mac(so I bought a bluetooth dongle). Switching from one device to another is very easy. It can only get connected to one device.
Fit - The smallest bluetooth earbuds money can buy in the market(I tried a lot ie backbeats go2, jabra sport, etc and they all look like I have a jawbreaker in my ear). The fit is great but when I ran it started to fall off with the sweat and all. The solution: Over the ear fitting. It has been excellent for me during running. I use the under the ear for leisure activities/plane trips because I can secure it around my neck when I temporarily remove them. Just google jaybirds on how to clip it properly(clips included in the purchase), it takes 30 seconds.
Things I hate - the case. OMG. Very poorly designed. It is huge and a pain to open/close. The comply eartips has irritated my ears, so I use the silicone(included too).
I disagree with other reviewers about not sounding loud enough, I never had a problem with it using spotify, pandora, itunes and even just watching from my mac. IT'S ALL ABOUT THE PROPER FIT. Ignore the reviewers that says the sound is tiny, they are not fitting it correctly or they didn't clean their ears.
TLDR: Just buy it if you're looking for a bluetooth earbud with good sound quality and comfortable fit. I spent too much time purchasing and returning the cheaper ones. Wear it over the ear when running. If the fit is not great, just return it but give it a shot :)
UPDATE(10/24/2015): After 2 months of use, the X2 has been amazing. No lost connections(not even once!), plus the new iOS displays the battery life now. I have been training for a half marathon and using it for traveling, it has not failed me. Devices used: macbook pro late 2011, ipad air 2, tomtom spark cardio + music, iphone 6s.
UPDATE(3/7/2016): The X2 has been solid. I have now been using it on a daily basis - I just discovered audiobooks lately and wear the X2 to listen to them on my way to work. Still no spotty bluetooth connections despite heavy use. I am using it for everything, I think I already got my money's worth. Battery life has not worsened after a few months.