On paper the two are similar. They each have various strengths and weaknesses that their counterpart doesn't have, but that's because they were built for different missions, and this also reflects in their design and their build. The Merkava's engine block is in front of the tank, something which leads to more mission kills, since an engine is relatively easy to knock out, but this also leads to increased crew safety, since impacting shells and RPG/ATGM's expend their energy on killing the engine instead of the crew.
The Merkava 4's pack an advanced reactive armor which is the best in the world at the moment, if I'm not mistaken.
In the end analysis, though, the main difference is always in the people inside the tank, and here Israel has the distinct advantage. Not because our training is better, more comprehensive or more thorough (I've never gone through Egyptian training, so I wouldn't be able to tell you...). The reason Israel has the advantage is because Israel is not fighting for a goal or an objective, like an invading army intent on wiping out the Jews. Israeli soldiers are fighting for their lives and the life of their country, knowing full well that they only have one chance, one shot.
It's like Pari mentioned, the invading armies can lose time and time again, they can always withdraw, regroup and reattack later. Israel has no backups, she can only lose once. It is this sense of desperation and urgency which will lead Israeli soldiers to take actions that are more daring and more risky than their opponents, and why they will always fight harder than their opponents.