I applied for Tier 2 migrant visa for myself and Dependent visas for my wife and daughter. I was very nervous after reading all the reviews, but the British consulate was very professional and quick in processing out application. Maybe we are the lucky few.
Timeline:
Feb 17: submitted online application
Feb 21: Biometric appt and sent application via ups overnight
Feb 24: Application delivered to the consulate at 10 am.
Feb 24: Email at 11;30 am confirming receipt and ready for review by ECO. I should mention that I paid for priority processing for all 3 of us.
Feb 25: Email saying our UK visas have been issued. The turn around time for a decision was around 24 hours.
Feb 28: Documents mailed back via provided prepaid shipping label from UPS
Mar 4: Documents received with stamped visas.
The only reason it took so long was because we had 2 weekend in between. From applying online to receiving back passports took only 2 weeks for us. I should mention that we have crystal clear criminal and immigration backgrounds. Also, only documents I had to provided were Degree Certificates, marriage certificate and birth certificate for my kid.
I would greatly recommend thoroughly reading the guidelines and giving them all they ask for in originals and copies. You must provide copies for each original if you want to receive them back including the passport bio page. The documents we provided are:
Primary Applicant
Originals to be returned:
1) 2 Passports (visa and I-94 for legal presence in the US)
2) Employment Authorization Document (EAD)/OPT card (legal presence in the US)
3) I-20 (legal presence in the US)
4) Bachelors and PhD Diplomas (English Language)
Other originals and copy documents:
5) Online Application form
6) VAF9 + Appendix 5 hand filled forms
7) 2 - 35mm x 45mm photos, 2 - 2x2 in photos, 2 - professional printer size photos with names on the back (6 total) (in white envelope)

Offer letter (Job and Salary)
9) Copy of Certificate of Sponsorship (Resident Labor Market Test, Salary and Maintenance)
10) Biometric Receipt
11) Priority service payment receipt
12) Self-Assessment Summary
13) TB test results
14) Copy of US visa, EAD/OPT card, I-94 (Arrival/Departure record) and I-20 (legal presence in the US)
15) Copy of Driver's License for proof of address
Wife:
Originals to be returned:
1) 3 Passports (visa and I-94 for legal presence in the US)
2) Employment Authorization Document (EAD)/OPT card (legal presence in the US)
3) I-20 (legal presence in the US)
4) Masters Diploma
5) Marriage Certificate
Other originals and copy documents:
6) Online Application form
7) VAF10 hand filled form

2 - 35mm x 45mm photos, 2 - 2x2 in photos, 2 - professional printer size photos with names on the back (6 total)
9) Maintenance Supporting letter from sponsor and Copy of Certificate of Sponsorship
10) Affidavit of support from primary applicant
11) Priority service payment receipt
12) Biometric Receipt
13) TB test results
14) Copy of US visa, EAD/OPT card, I-94 (Arrival/Departure record) and I-20 (legal presence in the US)
15) Copy of Driver's License for proof of address
16) Copy of Marriage Certificate
Daughter:
Originals to be returned:
1) 1 Passport
2) Birth Certificate
Other originals and copy Documents:
3) Online Application form
4) VAF10 hand filled form
5) 2 - 35mm x 45mm photos, 2 - 2x2 in photos, 2 - professional printer size photos with names on the back (6 total) (in white envelope)
6) Maintenance supporting letter from sponsor and Copy of Certificate of Sponsorship.
7) Affidavit of support from primary applicant

Priority service payment receipt
9) Copy of Birth Certificate
I want to mention here that me and my wife are Indian nationals and in the US on student visas and currently on OPT. My daughter is a US national.
I wish you good luck!!