First, if you can ascertain that the person/company trying to lease your land is a "flipper" I strongly suggest you don't do it. It is best to lease with the exploration company directly as you suggest, but often times this isn't possible (at least in early stages). It is often common that the exploration company (producer) will hire a landman company to lease anonymously on their behalf. Whether a flipper or a landman firm; they in essence are a middleman which would add costs to the gas/oil exploration company.
But a landman has the direct line to the client where a "flipper" is a speculator. The speculator will simply lease and lease as much as possible with the intent of some day finding someone (anyone) that would pay MORE so they make a profit. By contrast, a landman firm will have an payment schedule agreement already in place prior to the leasing action starts.
So knowing that what does a mineral owner (MO) do? I strongly encourage a MO to research who is trying to lease their minerals. Determine if they are flippers/investors, landman (directly for client) or the gas/oil exploration company directly (producer). If you can determine they are flippers, then walk away. If you can determine they are a shell (a new company recently formed to lease, then walk) and look to do business with established landman firm or best yet a producer directly. That doesn't necessarily mean that a small producer is better then a landman firm representing a big gas/oil client. So it is necessary to study the offers carefully.
So keep in mind that a landman firm or a flipper are providing a service to the final client and that is they have amassed a large MO acreage holding. Typically done anonymously and early in the leasing rush for a lower amount. This mass holding is worth something to the "client" and why they pay the landman or may acquire a flippers holdings. The key is a mass holding with 1000s of acres involved.
So specifically the question you have posed. If you have 300 acres and have an offer from a flipper can you contact a gas/oil exploration company directly and do better. Generally NO. Unless your tract is adjacent to mineral acreage that they currently hold. In this new shale exploration with horizontal drilling the drilling units typically require 640 acres or 1280 acres.
However, a possible strategy is to form a landowners group and try to get 1000s of acres with as much contiguous acreage as possible. Then you could assemble a bid package and submit it to major gas/oil exploration companies that have some activity or interest in the area. The more land the better. I was part of a 7,000 acre landowner group and we obtained offers from several big companies before selecting one. So the amount of acreage helped and then establishing a bidding environment helped to improve the terms; bonus, royalty and addendum details.