In my years of BYA games I have owned both of those, the M14 was actually my first airsoft gun I got three years ago (I still have it). If you are on a very tight budget the M14 is decent but lacks the FPS and range that you need a good sniper rifle to have. On the other hand the M14 is very durable for the price you pay and still works for me after three years.
The Well is the complete opposite, it has good FPS and slightly above average range but the gun lacks durability and wears down VERY quickly. As P90Airsoft said you will need to "upgrade the crap out of it". It lasted me only about 500-750 shots stock. Yes it does come with a scope and bipod but I would not buy it, instead save up some money and buy this-
UTG L96. It is my current sniper rifle and I love it. Plus there is no need to immediately upgrade it since it is outstanding stock. The UTG L96 is very durability, good FPS, good range, and easy to operate. Would rather use my L96 with out a scope than the Well with one.