Pandit Bhatkhande's book categorizes the Raga to the Vilawal that, as Rajan Parrikar's website corroborates. The vadi swar is Gandhar, and samvadi is Nishad, aptly so, because the meends involving these notes form the marrow of the Raga. Another noticeable facet is the sensual use of both Madhyams. The use of the Teevra Madhyam and its distribution with respect to the Shuddha variety appears to be different in different rendition styles.
I have heard many recordings of the Raga. Since I am inclined to the Kirana Gharana a little bit, I would start by mentioning Pandit Bhimsen Joshi and Smt. Gangubai Hangal's renditions of the Raga. Both of their readily available tapes start with the Vilambit bandish "Kaise Sukha Sove", which is very popular, and indeed a very beautiful one. I don't remember Smt. Hangal's drut bandish, and commenters are most welcome to remind me of it. However, I do remember Joshiji's drut, "Lat Ulajhi Suljha ja Balam", which is one of the sweetest drut bandishes I have heard. I have a recording of Ashwini Bhide Deshpande singing the same bandish, and it is quite attractive. Rashid Khan's performance of the Raga is amazing, and I keep on listening to it very frequently. There's a long recording of Pandit Ravi Shankar, which is amazing, and is played with his idiosyncratic style of playing the Sitar. I am listening to more of him these days. Pandit Ranadhir Roy's recording of Bihag is again, one of the better performances when instrumental renditions are concerned. He is just astonishing like his recordings of Tilak Kalyan and Jaijawanti that have been mentioned on this blog earlier.
I am looking for renditions of two Bihag bandishes that I learnt, but have not heard in recordings or concerts. The first one is a Madhyalaya bandish in Rupak Tala called "Aaye Sab Mile", a Sufi kind of bandish, which is a prayer for the saint Khwaja Mainuddin Chisti and has some interesting words. It says:
Khwaja Mainuddin, Garib Nawaj.
Chisti Peer Tum
Hind ke Bali Ho
Puri Karo Sab Man ki Kaaj
and there's immense scope of Laykari in it because of the Rupak setting. There's another bandish called "Chhup Jaa Re Chandni Raat", which typifies the Bihag-ish feeling, and portrays the Viraha that Bihag's a trademark of.
Two cents from my side. Contributors of this blog certainly have more to say. You are welcome to continue this post, so are the readers of the blog.