If you want to be competitive in Superhero City then you're going to have to purchase as many wearable items and Merit Abilities as you can afford.
A wide array of wearable items are available for purchase in Superhero City. These items will give the wearer various increases in their stats, much like in RPG video games.
All items are divided into 3 categories - amulets, bracers and rings. A player can only wear 1 amulet, 2 bracers and 2 rings at any given time. This limitation creates a strategic opportunity however. For example, while one particular amulet might give you a large attack bonus, a different amulet might give you an equally large defense bonus. And so the strategy you want to employ here is to equip attack based items only when you are actually attacking other people. The rest of the time you should be wearing defensive items.
Another strategy is to further refine what you have equipped by wearing 2 of the same rings and 2 of the same bracers depending on whether you are attacking or defending. So instead of wearing 1 ring that gives a 50% attack bonus and one that gives a 75% attack bonus, simply buy (and equip) 2 of the 75% rings to maximize your bonus.
The list of available items in Superhero City will change from time to time. The ones that change most frequently are those that cost Merit Points to buy. These items come in finite quantities and once they are bought up they are gone. Regular items will stick around much longer and will usually just have an item or two added to the list depending on the season, like a Christmas themed amulet or whatnot. These items are not as powerful as the ones that cost Merit Points though.
As was just mentioned, the most powerful wearable items in Superhero City are those that cost Merit Points. They come in limited quantities and are very expensive. Compared to top-notch Merit Abilities, which can cost 40-60 Merit points, these particular items can cost well over 100 Merit Points. Their bonuses are so large though that they are well worth buying. The only problem is that unless you're willing to buy Merit Points with real money, it will be quite a while before you can afford them.
Assuming then that you won't be buying Merit Points, it is best if you concentrate on obtaining Merit Abilities as they will give you the most bang for your buck.
These super powers differ from the regular Attack, Defense and Movement powers in two different ways. First, they cost Merit Points to buy. Second, they are much more powerful than regular super powers.
Merit Abilities come in 3 different categories or "classes" - Alpha, Gamma and Omega. Alpha Class abilities are the cheapest and least powerful. Gamma comes in second and Omega is first, being both the most powerful and the most expensive.
There will be 3 of each class on sale at any given time, with a 15% discount if you buy all 3 together. So in terms of saving, it makes sense to wait until you can afford to buy all 3 together.
Waiting is not always practical however, and buying a Merit Ability whenever you can afford it is never a bad idea.
This brings us to what NOT to buy with Merit Points. Aside from Merit Abilities, there is a small list of luxuries that are available for purchase. These include a Fight Refill (5 Merit Points), Energy Refill (25 Merit points), Extra Team Member (10 Merit Points), $10,000 (10 Merit Points), and finally, the ability to change your hero's name (1 Merit Point).
All of these are, to different degrees, a waste of hard-earned Merit Points and should be avoided in most cases.
Fights refill pretty fast on their own at the rate of 1 every 30 minutes. Plus, friends can send you free boosts to refresh fights. Energy as well refills rather quickly and like fights, can be refreshed by free boosts.
An extra team member is never worth it because they can never be as powerful as a real player on your team. Besides, real Team Building is more effective and most importantly, FREE!
As for spending 10 Merit Points to get $10,000 worth of in-game cash, that's just a joke. Money is easy to come by in Superhero City through fighting and by completing missions.
The ability to change your name could come in handy though. And because it's cheap, makes for a bargain if you're in need of evading your enemies.
At the end of the day however, if you want to be as competitive as possible in Superhero City, then Merit Points should only be used to buy Merit Abilities and wearable items.