Disclaimer: I'm not a viewer of Bigg Boss and most of my opinions are based on short clips, few WUs and forum discussions.
Priyanka Chahar Choudhary: I like her as an actress in Udaariyan. I'm pleasantly surprised that she is strong headed woman with an interesting personality. Most of the times, she over reacts at each and every thing but I didn't like how she was bashed at WKW every week. Sometimes I feel she deserves it but not always. It was monotonous. I didn't like how she manipulated Shalin to fight against Archana when he was quiet. But she is fast better than Shiv. Then, I find her relationship with Ankit as toxic no matter what. I am neutral about her.
Ankit Gupta: He is a very sorted personality and a very talented actor. But at the same time, he did nothing in the house. If not for Priyanka's angle, he would have been ousted a long back. But yeah, fandom support is huge. And simply, Bigg Boss is not his cup of tea. Not that, BB is meant for calm personalities but still it's all about game which Ankit never had on his own (his screenspace increased sometime after Wilcards, but it's too late to start a game if he really had)
Tina Datta: I don't know much about her and haven't seen her shows too. But her rift with Sreejita generated interests and got surprised about her old controversies with Sreejita and her old co-star. She seems to be very calculative and manipulative in the beginning and thought she could be a good leader. But it looks more like she is interested in making love angles. I expected a different version of her after Shalin's fake feelings exposed in front of her but in vain. Whatever she did with Sumbul is unforgivable but I felt bad when Touqeer and Sreejita assassinated her character. She probably had lost her path in the mess.
Shalin Bhanot: I have seen him in Naagin 4 and liked his acting and clearly had no idea about his past. Though I had followed Daljeet's news during her BB13 venture, I thought they were just separated. Never thought there is something else deep into it. But I'm not going to judge him based on past. The good thing about Shalin is his compelling screen presence which almost none of the male contestants had in this season. But yes, he is too fake when he was in relationship with Tina and his reaction when it was exposed to her... My god! In other scenes, I am not sure about his fakeness. I found his anger almost justified when Mr. Touqeer spoke I'll of him. Guess after that so called breakup, he was liked by people. But I feel he is trying to change his image from a violent guy to a joker.
Sumbul Touqeer Khan: She is just like the typical teenager who crave for attention and care. She tried to generate content out of other's issues (like how she did with Shiv Archana along with Shalin and Tina) but failed miserably. She prefers to play safe game sometimes. I don't know if it is right to blame her for revealing about Gautam Saundarya's bathroom matter and lying eventually. But anyone would think like that only when they see such a scene and it's natural to gossip. But I'm not sure when she lied about Vikkas. She is very submissive and get easily manipulated.
Gautam Vig: He is an underrated actor from what I have seen in Agni Vayu. But here, I feel he try to come across as an intelligent personality but he couldn't be. Sometimes I feel, he tries to benefit from Shalin's bad image in media by opposing (envying) him so that people would like him. But it didn't work much. His love angle with Soundarya made everything worse for him and no further comments.
Soundarya Sharma: I am not really sure about her. She might be a sorted personality but I don't think she has any big factor to stay these many days in Bigg Boss. But still, what is so special about her? No fandom support or contacts or content... Mostly I find her gossiping or else doing some exercises.
Nimrit Kaur Ahluwalia: She is one of my favourite actresses as I watched Choti Sardaarni. Even when the show was on air, there used to be many offscreen rumours about her. So I was excited to see her in BB to see whether they are true or not. She started off as the most promising contestant but now she is no less than a show piece or gossip generator. But I should agree, she is very good at being in good books.
Archana Gautam: I never found her entertaining though she provided a lot of content earlier. After her dirty words to Vikkas and Shalin, I lost my respect for her. Her mouth is a trash. I really don't want her to win or go to the finale. It would be a big disappointment.
Sreejita De: Since beginning, I got negative vibes from her though people liked her more than Tina. And it went right after her confession on Tina's character. But still, she did nothing. She is an example of Barking Dogs seldom bite.
Shiv Thakare: He can be a good player but he is trying to be a mere assistant of Sajid. Also he gives me creepy vibes especially when he instigated Tina by calling her 'dear'. I find Shiv's game is to provoke people and bring out the worst side out of them on him and play a sympathy card. The same happened with Archana but went worse as she strangulated him.
Sajid Khan: Only one word... Useless.
Regarding others: No idea.