Hi abdulaziz, welcome to the forums!
The, "Should I buy this pipe?" question will likely elicit a bevvy of responses.
I am with papipeguy, I have little experience with Big Ben, but have a few Savinelli pipes. The Big Ben pipes I've held and seen appear to be well put together and well engineered; as have the Savs. If I were shopping for a new pipe now I would set a price point, and then compare pipes of different manufacturers on a site like smokingpipes.com . Examine them, what do you get for your money with each factory/manufacturer (shape, size, finish, filter/no-filter)? Next, ask which pipes speak to you the most? I bet you reach for a pipe on your rack that you like aesthetically more often than a pipe which you just aren't in love with. For $150.00 you should be able to get yourself a lot of pipe.
I will say this, you may be able to get a pipe of higher quality/finish on the estate market. So looking at the estate pipe section of your online pipe-vendor of choice will help you explore all your choices.
Good luck, and let us know what you choose!
-- Pat