From my experience of using hacked clients, and being in communities of hacking groups.
Wallhax.com takes the number #1 spot by a mile.

Firstly,
The hacks are amazing and constantly updated. (Some games are dead, therefore hacks are currently dead too, but that's understandable.)
Extremely safe to use, I haven't been banned on any game while using the hacks provided by the client.
Support on the website is super useful and fast, any issues I had were resolved within 12 hours.

Secondly,
The hacks are super cheap! And wallhax.com offers a 3day trial for only 3$!
The good thing about wallhax is that you get ALL the hacks, for just one price. (Per month/3months/lifetime.)
With all of my experience of using hacked clients, and I've used atleast 4 different ones, wallhax.com provides the best Hacking experience, Support, and Communication.

To wrap things up, I wouldn't change anything that wallhax.com have done so far. The prices are amazing, and hacks actually work, and are undetectable. It's weird that they haven't raised prices for the quality that they provide. Overall, I am Extremely satisfied with everything, and cannot wait for future games/updates to the hacks.

Kind Regards,
~Mario <3