It may be helpful at this point to provide a brief summary of my thoughts on how these three compare.
All three software programs have strong original language capabilities. I don't think it would be too much of an exaggeration to say that there is probably a 90-95% overlap here. In other words, all three can do most of the same things in one form or another. All three, for example, make use of morphologically tagged Hebrew and Greek databases to enable a wide variety of simple and complex searches. The main difference is in the interface each uses for the searches.
It seems that the main fundamental difference between the three companies is in terms of their primary focus. BibleWorks focuses almost exclusively on the original languages of Scripture. Logos focuses on providing an extensive (and ever-growing) digital library to its users. Accordance appears to be focused on trying to achieve the best of both worlds - and to do this for Mac users.
The different primary focus of each program tends to define the strengths and weaknesses of each.
BibleWorks is strong in terms of the original language resources that come as part of its base package. It contains, for example, the Juoun-Muraoka Hebrew Grammar, the Waltke and O'Connor Hebrew Syntax, and the Wallace Greek Grammar as part of its base package. The optional add-on modules available from BibleWorks are all related to original language research. BibleWorks is a no-frills program, and this no-frills approach makes it the most affordable of the top three.
The main weakness of BibleWorks, in my opinion, is that it does not come in a Mac version. It can be run on a Mac by using software such as Parallels Desktop, but ideally, it could be offered in both a PC and Mac version. BibleWorks also does not yet have the syntax search capabilities available on Logos.
Logos is strong in terms of the sheer number of resources it makes available. There are over 700 resources on the Scholar's Library Gold version that I reviewed. Logos is also the only program that currently has any kind of syntax search capability for the original languages. The Logos interface is one of the most intuitive of the three. It resembles a basic website interface. The amount and kind of resources is very helpful. To be able to do a search and see results in original language resources, commentaries, sermon illustration books, etc. is a strong point.
The main weakness of Logos is the cost. Even with the available discounts, the high price could be out of the reach of many pastors and seminary students who are trying to make ends meet. The other weakness of Logos is a byproduct of one of its strengths - namely the large number of resources. In the first place, most users will probably find a large number of these resources to be extraneous. Second, the large number of resources slows down searches - sometimes dramatically.
Accordance is strong in terms of its original language capabilities and in terms of its additional digital resources. Accordance also scores points in this reviewer's book for being designed specifically for the Mac operating system. It can be run on a PC with an emulator, but it was designed with the Mac in mind. Accordance also has the best graphics package of the three. The maps and overlays are simply much nicer looking than those available with either BibleWorks or Logos, and the 3-D map function is a definite plus.
Although not as expensive as Logos, price is still a weakness for Accordance. Like Logos, Accordance has discounts available, but many pastors and students could find it outside their means. Accordance also has a "buffet style" catalog, which is a strength from one perspective and a weakness from another. It is a strength in the sense that you only pay for the resources you want. You aren't forced to purchase a lot of digital books you do not need or want. On the other hand, the catalog is a bit confusing to understand with the different libraries and levels. It doesn't have the intuitive self-explanatory nature of the software itself. It also means you could spend a lot of time installing numerous discs and unlock codes.
WHICH ONE IS BEST?
So which software program is best? I think this ultimately depends on what it is you want to be able to do with the software and what you can afford. All three have relatively easy to learn interfaces, so that issue really boils down to personal preference.
What you want to do is the main question you should ask yourself before purchasing one of these programs. If your only interest is getting resources for the study of the biblical languages, I believe all three are sufficient, but BibleWorks is likely the best buy because of its more up to date original language resources that are contained in its base package. If you do not already have some level of competence with the original languages, however, BibleWorks will not be very helpful.
If you are a busy pastor and your main goal is an easy to use tool that will help with sermon preparation, Logos might be the way to go since it puts a wide variety of sermon preparation resources in one place. Logos is also the program of choice for those who are interested in building a large digital library of theological and biblical resources.
Teachers and students who want access to a variety of tools and an easy to learn interface will find that Accordance probably has much or most of what they want and need. Mac users will certainly want to take a close look at Accordance.
Those are some basic thoughts, not hard and fast rules. After reviewing all three, BibleWorks is still my software program of choice because of what I use it for. One of the others may be a better choice for someone with different uses in mind.
That said, my advice to anyone considering the purchase of any of these is to visit the three websites and read everything you can, including linked reviews. If available, watch the demo videos to get an idea of the actual way the program works. The purchase of any of these programs will involve a significant investment of money, and it is best to know what you are getting before spending anything.
Look at the features available on each. Look at the resources that come with each and those that are optional add-ons. Are the resources available the ones you need? What will it cost you to get everything you want?
Look at the system requirements. If you think BibleWorks is the program for you and you have a Mac, know that you will need additional software like Parallels desktop to run it. If you think Accordance is the program for you and you have a PC, know that you too will need additional software. If you like what Logos has to offer and you have a Mac, know that the Mac versions of Logos do not necessarily have everything the PC versions have (see my review of Logos Gold).