I just installed a Davidsen crystal in my 127 and it was completely worth the money. It really does make the entire watch look better. By the way, the crystal in my watch was supposed to be genuine sapphire, but it exploded after being bumped VERY lightly. Verify with the dealer you choose that it is genuine before you give them your money. Sometimes they "forget" to put the word "Synthetic" in front of the word sapphire in their ads.
If budget is a concern, try buying a used 127 from an established member who you trust, then purchase the crystal from Davidsen, or Vaccum. Vaccum will install it too. It will run about $80, plus money transfer fees, directly from Davidsen.