Here is 'Ali Laraki's opinion on Deoband. It is not flattering.
Whenever I talk about deobandis, I talk about those who represent the teachings of Deoband in South Africa and the UK. Those are the only ones I know and have met. I do not speak about the debandis of India because I have never meet them, but those of SA and the UK suppose to represent them.
There is a very simple rule of thumb which is the following in Arabic
فاقد الشيء لا يعطيه
A loose translation will be: If you do not have something, you cannot give it.
I am so sorry, but I cannot accept the claims of real tasawwuf from the deobandis of the UK and SA. At list not from their majority, there are always exceptions. If they had any real tasawwuf other that a formal affiliation to such and such tariqa, they would have expanded the Deen among the Zulu, Sotho, Tswana and other African nations. The same among the British natives.
Historically, when the people of tasawwuf enter a land for trade or other reasons, the final result is the expansion of the Deen among the natives of that land. I am so sorry, but I could not see that done by our deobandi brothers. So the touchstone of the Deen is that it is transmittable. There is in it a light that attracts the people. Deobandis can't even keep their own Indian and Pakistani young generations in the Deen. They are loosing them. Just get into a mosque and then into a club to see it.
And what I said also applies also to the Barelwis. I know that what I am saying will probably bring me the enmity of both those groups, but that is not what concerns me. What concerns me is that they have became rigid in their positions claiming they are the protectors of the Deen and they are loosing everything.
They could have the Africans in their side in South Africa, but they were not interested in teaching them the Deen. They only wanted to exploit them or to turn a blind eye to how the traders among them treated their black employees (or course, because the traders are the ones who pay their nice masjids and Darul Ulums). Now the are under the thumb of the Africans and in a worst position than when they were under the whites.
As for here in the UK, they are acting in the same way. They are not interested in the least to expand the Deen. They want to get as much as they can from the UK but they give them not the most precious treasure they have: La ilaha illa Allah, Muhammadun Rasulullah. Well, they are loosing their own people. In fact, the religious and intelligent amont their youngsters are turning to sources other than them for their Deen. They are tired of the suffocating, puritanical and subservient to the financial system of the kuffar version of the Deen deobandis promote.
And as I said, Barelwis are not better than them in this aspect. But I have to recognise they are more open and welcoming to new ideas than the deobandis.
When I say new ideas, I say it in the sense of revival of the Deen not in the sense of blameworthy innovation.
Anyway, they either renew themselves or they will soon be a used ticket.
And Allah knows best