It is true that both the spiritual seekers would end up getting entry into divine realm of God and will be completely satisfied forever, if proper spiritual practice is followed.
Here again Islam does not get into details of divine realm. Divine realm in broadly classified into three major sections.
1. Brahm happiness, (Unity of soul with formless God.)
2. Paramatmic happiness. (Related seeing Lord)
3. Devotional happiness. (Related to Loving God)
Islam discusses only the first one. While Hindu speaks of all three.
All the options provide infinite, never ending happiness but the quality would differ.
There are many classes in each section. But this broad classification would help in deciding where you want to head in spiritual realm.
If you are interested in union of soul with God through merging of soul with God the first one should be your goal. In this case your mind is dead and you are left with no senses. Mind is the obstacle in fetching infinite happiness. Problem is solved by killing it. This way you experience complete peace through divine light.
If you would like to have your body and mind intact and transform them into divine you can opt for second and third option.
The third option is the best one as one could treat God just same as one would treat king, master, friend, son, lover.
Thus you will find that merger of soul with God is a destructive method while devotion is a constructive way.
It has been already stated that all three options lead to infinite happiness but of varying quality.
Hindu puts happiness through loving relationship at the topmost. And happiness through unity with formless God at the bottom-most. The choice is left to the soul.
All these explanations or answer to the frequently asked questions are important to put yourself on a spiritual track. In their absence spiritual aspirant will be confused about intent of God.