What the Scholars have said about this Night:

1) The general virtue of this night has been accepted by many great Ulama of the past. From among many great scholars which have agreed to the virtue of this night are: Umar ibn Abdul-Aziz, Imaam al-Shaafi’ee, Imaam al-Awzaa’ie, Attaa ibn Yassaar, Imaam al-Majd ibn Taymiyah, ibn Rajab al-Hambaliy and Hafiz Zaynu-ddeen al-Iraaqiy (Rahmatullaahi alayhim) .
Refer Lataiful Ma’aarif of Hafiz ibn Rajab pgs.263-264 and Faydhul Qadeer vol.2 pg.317.

2) Even Ibn Taymiyya — the putative authority of “Salafis” — considered the night of mid-Sha`ban “a night of superior merit” in his Iqtida’ al-sirat al-mustaqim:[Some] said: There is no difference between this night (mid-Sha`ban) and other nights of the year. However, the opinion of many of the people of learning, and that of the majority of our companions (i.e. the Hanbali school) and other than them is that it is a night of superior merit, and this is what is indicated by the words of Ahmad (ibn Hanbal), in view of the many ahadith which are transmitted concerning it, and in view of what confirms this from the words and deeds transmitted from the early generations (al-athar al-salafiyya). Some of its merits have been narrated in the books of hadith of the musnad and sunan types. This holds true even if other things have been forged concerning it.
( Ref:Ibn Taymiyya, Iqtida’ al-sirat al-mustaqim (1369/1950 ed.) p. 302.)

Ibn Taymiayh also said 
“ As for the middle night of Sha’baan, there are various narrations that have been narrated regarding its significance and it has been reported from a group of the Salaf (predecessors) that they performed Salaat in it individually, hence, such a deed cannot be disputed.’
(Majmoo’ al-Fataawa ibn Taymiyah vol.23 pg.132)

3) Imam Suyuti (Rh)says in his Haqiqat al-sunna wa al-bid`a:“As for the night of mid-Sha`ban, it has great merit and it is desirable (mustahabb) to spend part of it in supererogatory worship.”
( Ref: Suyuti, Haqiqat al-sunna wa al-bid`a aw al-amr bi al-ittiba` wa al-nahi `an al-ibtida` (1405/1985 ed.) p. 58. He adds: “However, this must be done alone, not in congregation.”)

4. Imam Haskafi ( Rh) said in his Durr al-Mukhtar, one of the primary references in the Hanafi school:
“Among the recommended [prayers] are on. . . . the nights of the two Eids, the middle of Sha`ban, the last ten of Ramadan, and the first [ten] of Dhul-Hijjah”.

5. Imam Nawawi ( Rh) mentioned in his Majmu`, where he also quoted Imam al-Shafi`i from the latter’s al-Umm that it has reached him that there are 5 nights when dua is answered, one of them being the night of the 15th of Sha`ban.