For example, would any other damage to the home occur (foundation or otherwise) if you 'allowed' water to enter the basement to be caught in an INTERIOR perimeter water-trough system (where it's 'diverted' to a sump pump and removed that way?) In this example, the interior 'fix' is a bandaid if other damage were to occur by allowing water to continue to 'permeate' from the exterior of the house to the interior.
Another example, if the landscaping around the exterior of the house can be re-graded to allow for proper sloping where water can 'run away' from the foundation (and subsequently 'diverted' to a safer area), why dig at all?
And yet another example, if the source of the water is from missing or leaking/bad gutters and downspouts, then correct this first because it's probably the cheapest way to go. In the next heavy rain, put on your boots and raincoat and get an umbrella, and inspect the roof and gutter and downspouts around your house. Watch where the water goes once it hits the roof, enters the gutters (if present), and comes out the downspouts. Assuming the 'system' is clogged somewheres along the way, you may fix your problem by simply cleaning the 'problem' from your above-ground drainage system!
In short, before you spend large amounts of $$$, try and eliminate the obvious. Make sure you have gutters and downspouts and they're NOT leaking or running over. Make sure your downspouts extend at least 3' FROM your foundation. Have at least a 1/4" per foot grade AWAY from the foundation over a distance of 3'. (That's 3/4" drop for 3' away from your foundation. The more the better!) Make sure water doesn't 'run back' towards your foundation. Make sure your neighbor's water isn't the cause of the problem (as was a case at MY house for 3 years before I 'caught' it!) Once you 'fix' these issues, you'll be in a much better 'position' to decide if doing an interior fix is better or worst than an exterior one.
Yes, it's hard to get objective info. Why don't you 'play' one contractor's solution against the other solution??! Let them tell you why it's best to do one vs. the other. Have a few contractors come in. Then you'll hear the 'same thing' in different words. In due time, you'll be a much better informed consumer. I wish I could see your 'problem' from here. My best to ya and hope this helps.