Fantastic experience with Yes tourism. Specially "Saurav ji", he was very supportive. Whenever you require any help during trip, he will respond quickly and will solve your problem.
My Sikkim trip(Gangtok-Lachen-Lachung) was fabulous. Cab drivers provided by "Yes tourism" were friendly and well trained. Hotel were good and view from hotel room was amazing. At end of every day, staff of Yes tourism will call you and update you about the next day plan and cab drive's number.
And most important Natural beauty of Sikkim will defiantly entice you.