As something new comes out it has issues or drawbacks, being the first of its kind makes Google Glass the same. Although it is still in beta stage and will remain in beta for quite some time, it is not up to the mark for Google standards.
Let's start with the hardware limits until now.
With a mere 570 mAh lithium-polymer battery, it doesn't have a very long life. If used continuously it will work for 4-5 hours but the advantage of such a small battery is that it charges in less then 2 hours. Surely battery capacity will increase over time.
It heats up very quickly, continuously using it for 5 minutes heats it up and shows up a message "Google Glass needs to cool down to work properly", although it works but it starts to lag when heated, so I need to put it down for some time to use it again. Although you wouldn't feel the heat on your ear or anywhere near it so at least there is no need to worry about that, I am sure Google Glass engineers are working on it.
Then comes the price point, why is a multi-billion dollar company like Google charging upward of $1500 for a single glass whose parts costs less than $200? The answer is simple.
First, its not ready yet. It's only in development and if you provide consumers an unfinished product they are going to discard it. Google doesn't want that.
Secondly, Apps; there are not many apps available for Google Glass as of now, so Google is creating a base of apps before the final product is ready.
So by keeping the price high Google is limiting the product to a selected user base that are really interested in it and will work hard to improve it.
The next biggest concern that Google Glass is facing right now is privacy. Google Glass has been criticized continuously for this. It has been banned in many pubs and bars in some cities in the US. Some people have engineered a word for people who use Glass in public, though I don't want to mention it here. People think that just because you have a camera mounted on your face means you are recording them secretly. If someone wanted to record you secretly why would he put a camera on his face? Glass is new and people are afraid of it. This is what is happening in the US right now. People who don't understand the technology can't embrace it and are only going to criticize it. Its like introducing camera phones all over again. First they were banned from certain places now no one will buy a phone without a camera.
I have not taken the glass out in public myself, except for the C-SharpCorner event in April. If you were there you might have seen it. At a technical event I expected everyone to be excited and those who got to experience it had many questions.
In my view, given more time Google Glass will be great and the next big thing. Just wait and watch out.