While $115 may seem expensive, try accurately boring a grid of 20mm holes on 96mm centers in 3/4 MDF. I have for a table for our retirement community shop - - its a pita. Plus the MFT material seems denser and more water resistant than garden-variety MDF. And the single-thickness has proven sufficient the last several years on my original 1080s. Still dead flat.
Olympia Tools is a bit of a lesser known manufacturer. While they offer a wide range of products for a variety of construction fields, they are definitely more of a budget option. That said, Olympia Tools is one of the few brands that manages to produce a reasonable quality at a low price which makes them a solid choice for customers looking to get the best bang for the fewest bucks.
Permanent or Portable? This is a distinction that decides much about your bench choice: Is it to remain stationary or must it fold, roll, or otherwise make itself scarce between jobs? Large, heavy benches are more stable and, in general, more adaptable to different jobs (sometimes several at once). But the bigger the bench, the more hassle involved with stowing it.
When the top is done, we want the edged MDF and the oak countertop to have exactly the same dimensions, and for their width to exactly match the width of the base.I could see three ways of doing this: 1, join the MDF to the countertop and use my belt sander to sand down their joined edges to match the base; 2, join the MDF to the countertop and use a hand plane to plane down their joined edges to match the base; or 3, use a flush-trim bit against a straight edge to route the MDF to the width of the base, then join the MDF to the countertop and use the flush-trim bit to route the countertop to match the MDF.