Which of the devotees are more perfect, those who ever steadfast, continuously worship you or those who worship impersonal and unmanifested(invisible form)[or yours].

The blessed Lord said:
Those who by fixing his mind on me, steadfast in me, always worship me, is extremely merged in me. I consider them to be the best among yogis(or devotees)

But people with evenness of mind worship the imperishable, the indefinable, the invisible, the omnipresent, the unchanging, the non-moving and the permanent, by restraining the multitude of senses, worship me, they all working for the welfare of mankind also attain me.

But greater is the vexation of those whose minds are thus attached to the un-manifest. For the way of the un-manifest is onerous(hard) for embodied beings to follow.
Or
Extremely difficult is for those who worship an invisible, for the progress in that discipline is hard to make for embodied beings [like Human].

For, those who dedicate all their actions to Me, holding Me as their supreme goal, intent on Me and who worship Me, meditate on Me with exclusive devotion and whose minds are thus focused on Me, O Partha, I soon become their savior from the fatal ocean of death and rebirth.

Fix your mind upon me alone and engage all your intelligence in Me. Thus, you will abide in Me alone hereafter; there is no doubt

If now, you are unable to center your mind on Me in deep meditation, then seek to reach Me, O Arjuna (Dhananjaya), by the Yoga of constant practice.

If even after practice you are not able, then with Me as the singular goal let the performance of your actions be directed towards Me and you shall attain perfection.

If, however, you are unable to work in this consciousness (Consciousness of Shri Krishna), then try to act giving up all results of your work and try to be self-situated.

Better indeed is the wisdom than the rituals (the practice of devotion), however, meditation is better than wisdom and better than wisdom is the renunciation of fruits of action — for by such renunciation one attains peace [of mind].

One who has no animosity with for any being, who is a friend of everyone, who is compassionate to all., is free from attachment, and egoism, and maintain equanimity of mind in joy and sorrow, forgiving, ever satisfied, united with yoga, have a strong determination in God and have consecrated his mind and intellect to me. Such a devotee of mine is very dear to me.

He by whom the world is not afflicted, and who is not afflicted by the world; who is free from mundane pleasure, envy, fear, and anxiety; is dear to Me.

One who is free from expectations, who is uncontaminated, skilled, impartial, and free from anxiety, is ready for new challenges, who have renounced every undertaking, and who is devoted to me— is dear to Me.

One who is full of devotion to Me, who rejoices not, nor hates, nor grieves, nor desires, and who renounces both auspicious and inauspicious things — such a devotee is dear to me.

One who is equal to both foe friend, who is equipoised in honor and dishonor, heat and cold, happiness and distress, and who is free from all attachment, to whom both censure and praise are equal, who is silent [when praised or abused] and content with any condition, who doesn't care for any residence, who is steady of mind, and who full of devotion— is dear to me.

But those devotees who adopt this ambrosial virtuous conduct (dharma) as taught above, who are full of faith and who regard Me as the Supreme — they are exceedingly dear to Me.