When you are looking at buying a new flute, there are a couple of options that can help with the 3rd octave E. The first is the split E mechanism. The split E separates the action of the upper and lower G keys, allowing the lower G key to close when high E is played. (Here is a link to a great illustration on Miyazawa’s website.) This allows you to play the high E without worrying about intonation or cracking the note, especially when playing piano or softer. It can also make it much easier to slur between high A and E.
The split E mechanism uses an extra rod, which can add a little bit of weight to the flute and it must be put on during the manufacturing of the instrument; it cannot be added later. Some find that the extra weight is cumbersome and the extra rod that is required hits the right hand 1st finger. Others notice that these issues go away after some time is taken to get used to the feel of it. The split E is mostly available on offset G flutes, but you can get it on some inline flutes, however, some report that the mechanism causes binding on an inline G flute. There is also the option (usually only on handmade flutes) of an on/off switch or clutch that operates the split E. With this you can actually deactivate the split E. Some manufacturers are making the split E standard, but often times you have to pay extra for it; somewhere between $150-500 depending on the manufacturer.
Another option for the high E is the high E facilitator (or lower G insert). This is an insert, which can be donut or crescent shaped, that is placed in the lower G tonehole. The insert actually makes the tonehole smaller, decreasing venting. It does basically the same thing as the split E, but it is more lightweight and cheaper. One con is that it can lower the pitch of A in the first two octaves. Several manufacturers are making the E facilitator standard if you do not get a split E mechanism. Also you can have the high E facilitator added or removed at any time; it doesn’t have to be put on at the time you order the flute.
My best advice in determining whether or not you should get one of these options is to try out flutes with and without them. Some flutists feel that you shouldn’t need any extra bells and whistles on your instrument and you should just toughen up and learn to play it the way it is. Others will take all the help they can get! It’s totally personal. However, I will say that there is no magic fix for any and all difficulties you may run into with flute playing. You still have to practice! 🙂