Great app for the price. Not the prettiest interface but it works which is what's most important ...

I tried a few Metafields apps, starting with the cheapest and working my way up...I've now been using this app off and on for a few weeks and, while its output format isn't the best (one row per product per metafield, rather than columns), it's perfectly workable for someone with Excel skills and I find it rather good!
Apart from the bulk export and import facilities (more of that in a minute), the display of information is good and clear. You can select product, collections, whatever else Metafields, to keep things tidy and when you list a single product or collection, or whatever, you're met with a full list of the Metafields applicable to 'whatever you're looking at', along with values. Any or all may be updated on that page, with one 'Save' button. New Metafields may also be entered here (and which then apply to all of that genre -products, collections, etc.). You can also perform a search so you quickly arrive where you want to be.
Simple, intuitive, comprehensive.
The only problem....is that although the app exports a nice csv file, which may be read by Excel and worked on within Excel - the export from Excel (in UTF-8 format, then opened and saved by Notepad in UTF-8 format, to ensure the file *really is* in UTF-8 format, as Excel doesn't do a good job with that) - cannot then be imported back into Metafields2, as there are some 'dodgy' characters hiding there at the beginning of the file.
However...with help from Joe and some experimentation, I've found it's possible to do all the above, working in Excel to do the 'bulk of the job', then open the exported csv file in Google Sheets - and then just save it. This results in a perfectly serviceable, *proper*, UTF-8 file that can be imported back into Metafields2.
Maybe a long winded review, but if it helps anyone with similar problems in the future...I think the app deserves it. It's a good app.

Unless you are a developer, this app won't help you. Set up is easy. Creating metafields is easy, but then doing anything with them is where this app falls down. Shopify doesn't give you any access to the fields (in product export for example) so you have to use the export utility in the app. The problem is that creates a line per product per metavalue, which unless you are going to throw the results into a SQL database, is beyond useless.

I can see the point of the app for some people, but it didn't solve our problem for creating the technical details as fields on products as a simple grid layout for our price list.