Between Therarava and Mahayana, there is one thing for sure - you can find more similarities than differences.
In term of view, I can't find the difference. I can find even heart sutta view within Pali suttas.
However, in terms of technique of practices, they are differences.
In Theravada, good and bad is separated as something distinct. Therefore, in the way of practice, you adopt the good one, and you abandon the bad one.
However, in Mahayana, particularly Vajrayana, it is only at the beginning of your study, you are introduce to good and bad as something distinct.
At the latter part, you are introduced to the view that actually between good and bad, that interpretation is coming from your side. From the phenomena or object itself, they themselves do not have value. They are not good, bad, or neutral.
Because of that, at the advanced level, you will be trained in the situation that use your distractions or desire, or any negative things as your path. This advanced teaching is also known as using adversity as your path.
Theravada tradition have some similarity, particularly the forest tradition. However, in forest tradition, it is your physical adversities living in the forest that you use mainly as your path.
In Vajrayana, it is your destructive emotions that you use as your path. In Theravada, destructive emotion is abandoned.
But in Vajrayana, destructive emotion is used as the path. This is like you are using the poison as the medicine.
In you are extremely angry, in the beginning of Vajrayana (which is Mahayana in general), you will be taught to subdue that anger by using antidote.
But, at the advanced level, where you already have the ability to keep a distance with your anger, instead of subdue or abandon it, you should learn how to use that.
Anger has exceptional quality. Its clarity and its energy can be beyond your limit. If at that particular moment, you have the ability to stay still and just look at the nature of the anger, when it arises, and can feel the non-identity of that anger, the clarity and its intense energy can give you a very very strong impression and a very deep direct experience of anatta.
In just 1 extreme and furios anger, if you can know the nature of anger - which is anatta, and freedom - that just 1 instance is enough to give you the glimpse - what does it mean by anatta and freedom.
Another example is desire.
Do you realize that it is far far easier to be mindful when you do a meditation instead of playing your favorite game?
If you can be very mindful and fully aware and still during your game playing, meditation is peanut.
So, instead of you abandon your desire in whatever activitity, you purposely go and do it, with your awareness ability. It will improve your ability in anatta substantially.
In Vajrayana, anatta is taught to be realized in intense activitities and in poisonous activity.
Not all people are able to do it and are agree with it. Some people really have the view that this nature, this universe is really divided into good and bad. So, if you want to practice, only through the good path you can progress, not in the bad path.
But some people see that this nature is not good nor bad.Therefore, whatever path he or she uses can become the path.
In Vajrayana, attachment is used to destroy attachment. Craving is used to destroy craving. Desire is used to destroy desire.
Some use attachment, but they are getting worse in the sense they get more attachment. So, all of them really depends on your intelligence and your self-contraint. You must know your limit.
If you think it is only through the good path, your buddhahood can be achieved, Theravada is the safe bet.
But, if you naturally think in reality, there is actually no good and bad, and everything is possible as the path, it is up to you where you want to train yourself.
I am not here nor there.
I am not right nor wrong.
I do not exist neither non-exist.
I am not I nor non-I.
I am not in samsara nor nirvana.
To All Buddhas, I bow down for the teaching of emptiness. Thank You!