I would like to add my personal view, which I see somehow between the two oppositions. I suggest a very important cause of the dispute is a different way of access to Epicurean philosophy.
The very common approach of reading the letter to Menoeceus is very clear in its essence. The letter argues, that we should prefer a life focusing on a peaceful state of lifing. It is argued, through making us independent from goods we do not need, wrong beliefs, fears etc. we achieve the best life imaginable and become generally independent from the difficulties of the world. The main problem is, that this approach doesn't refer to Epicureanism as a wider system of knowledge. Many thinkers only refer to the ethics as presented in letter to Menoeceus (additionally Principal Doctrines, Vatican Sayings) but do not apply Canonics and Physics, which they consider as a different point of interest.
For a person who studies all three main branches of Epicurean philosophy and even tries to combine and interconnect, it's something different. Understanding Epicureanism as a holistic system reveals that pleasure occurs in the beginning. It's a central part of Epicurus' epistemology. It is so important, because it occurs naturally. Searching for pleasure is not an abstract idea, it's an aim that is intrinsic to every lifing being.
In my opinion, Epicurus understood rightful, that pleasure is natural and central for every lifing being. We are not able to choose, we have to handle with our attraction to moments, which we perceive as more delightful than others.
In the Epicurean world, nature sets the standards. Epicurus reflects pleasure and comes to the conclusion, that it has to do with the conditions of our being. This is why he distinguishes between natural and not natural, necessary and not necessary. In other words: There is this basic impulse called pleasure and Epicurus examines this term in relation to the fundamentals of being alive.
In conclusion, we get an approach to the term pleasure which stretches from the Canonics to the Ethics by corresponding to the Physics.
In my personal opinion, Epicurus is neither looking for painlessness nor for pleasure as pleasure on its own. He tries to find out what a human is in itself. This is why he focuses on senses, feelings and anticipations. In relationship to a theory about the functioning of the world (physics) Epicurus derives his conclutions about how to conduct.
Consequently, satisfying all natural and necessery desires is the highest level of being. But being a sensitive being also means, that there are differencies in how this natural desires can be fulfilled and perceived. This is the flavour, which can tend to be not necessary (as Diogenes Laertios explains). This is why Epicurus advices only to fullfill natural but not necessery desires if they do not harm.
Finally, my personal view puts 'painlessness' in the centre, but it never occurs as that abstract idea as the word tends to appear. Ataraxia and aponia are related to the world made of atoms, which means that they will never exist perfect or erase the relationship with the world itself. We perceive painlessness only as a pleasureful state because it means, that we acquire everything what our natural fundamentals are looking for. This position is an important part of Epicurus' way to absolute freedom, but it remains only, if we remain near to the given fundaments, as set by nature.
As Lucretius tells to us at the beginning of book two of De Rerum Natura:
'Tis sweet, when, down the mighty main, the winds
Roll up its waste of waters, from the land
To watch another's labouring anguish far,
Not that we joyously delight that man
Should thus be smitten, but because 'tis sweet
To mark what evils we ourselves be spared;
'Tis sweet, again, to view the mighty strife
Of armies embattled yonder o'er the plains,
Ourselves no sharers in the peril; but naught
There is more goodly than to hold the high
Serene plateaus, well fortressed by the wise,
Whence thou may'st look below on other men
And see them ev'rywhere wand'ring, all dispersed
In their lone seeking for the road of life;
Rivals in genius, or emulous in rank,
Pressing through days and nights with hugest toil
For summits of power and mastery of the world.
O wretched minds of men! O blinded hearts!
In how great perils, in what darks of life
Are spent the human years, however brief!-
O not to see that nature for herself
Barks after nothing, save that pain keep off,
Disjoined from the body, and that mind enjoy
Delightsome feeling, far from care and fear!
Therefore we see that our corporeal life
Needs little, altogether, and only such
As takes the pain away, and can besides
Strew underneath some number of delights.
More grateful 'tis at times (for nature craves
No artifice nor luxury), if forsooth
There be no golden images of boys
Along the halls, with right hands holding out
The lamps ablaze, the lights for evening feasts,
And if the house doth glitter not with gold
Nor gleam with silver, and to the lyre resound
No fretted and gilded ceilings overhead,
Yet still to lounge with friends in the soft grass
Beside a river of water, underneath
A big tree's boughs, and merrily to refresh
Our frames, with no vast outlay- most of all
If the weather is laughing and the times of the year
Besprinkle the green of the grass around with flowers.
Nor yet the quicker will hot fevers go,
If on a pictured tapestry thou toss,
Or purple robe, than if 'tis thine to lie
Upon the poor man's bedding. Wherefore, since
Treasure, nor rank, nor glory of a reign
Avail us naught for this our body, thus
Reckon them likewise nothing for the mind:
Save then perchance, when thou beholdest forth
Thy legions swarming round the Field of Mars,
Rousing a mimic warfare- either side
Strengthened with large auxiliaries and horse,
Alike equipped with arms, alike inspired;
Or save when also thou beholdest forth
Thy fleets to swarm, deploying down the sea:
For then, by such bright circumstance abashed,
Religion pales and flees thy mind; O then
The fears of death leave heart so free of care.
But if we note how all this pomp at last
Is but a drollery and a mocking sport,
And of a truth man's dread, with cares at heels,
Dreads not these sounds of arms, these savage swords
But among kings and lords of all the world
Mingles undaunted, nor is overawed
By gleam of gold nor by the splendour bright
Of purple robe, canst thou then doubt that this
Is aught, but power of thinking?- when, besides
The whole of life but labours in the dark.
For just as children tremble and fear all
In the viewless dark, so even we at times
Dread in the light so many things that be
No whit more fearsome than what children feign,
Shuddering, will be upon them in the dark.
This terror then, this darkness of the mind,
Not sunrise with its flaring spokes of light,
Nor glittering arrows of morning can disperse,
But only nature's aspect and her law.
Lucretius. De Rerum Natura. William Ellery Leonard. E. P. Dutton. 1916.