My wife and I recently treated ourselves to a couple of iPhones (of the 3gs variety). These are the first smart-phones we have owned, and I can’t imagine life without them now. I never really thought that I needed a piece of technology quite like this, but then Logos had to go out and make an app. that would give me the ability to view many (and I do mean many) of the books that are currently in my digital library. So my cellular upgrade from a Razr to the iPhone is really Logos’ fault (they should really offer to pick up part of the tab on this, or at the very least throw in some additional digital books).

Below are a few of my thoughts on this app.:
Accessibility:
If you are a user of a base product in version 4, then you are eligible to access many of the books that you currently use through your iPhone now. If you are still using version 3 of their program or even earlier incarnations, then you will not be able to access the content of your digital library. I suppose this is another way to encourage folks to upgrade their current package. However, if you want to use the basic app. (and you don’t fit into the above category) you can download it and get access to several free Bibles anyway.
At the moment, Logos is only working with the iPhone platform, which means if you have a BlackBerry or an Android you are out of luck (although I hear that there will be an alternative option by logging into a Logos’ maintained website, http://library.logos.com). (edited for correction, the previous website was incorrect. Thanks, Mike.)
The Cost:
Many of the Bible Software apps. cost money and more than I have to spend, especially if I want the ability to search/read original language resources (LXX, BHS, DSS, CAL Targumim and etc.); however, I don’t want to pay additional money to read digital resources that I all ready own. Logos’ forward thinking has made it possible for me to access my software through another device using the same cloud that currently manages my resources for my p.c. All of this is accomplished at NO additional cost to the user!
General Impressions:
I literally have access to several hundred resources. The most important to me are those dealing with the Hebrew language, the BHS and DSS Sectarian literature are among those on this list. The display of Masoretic pointing (in texts which are pointed) still needs work and at times are jumbled, but in landscape viewing these marks are mostly readable.
If you are reading the Hebrew Bible using Andersen Forbes Analyzed Text (commonly referred to as AFAT), and can’t remember what a Hebrew word means or if a verb is a Qal or a Piel, then just tap and hold your finger down over a word until the parsing information and gloss appears. This is a fantastic feature for a quick study on the go!
Unfortunately not all of my lexicons (i.e. HALOT or Holladay) are available yet on my iPhone (much of this is due to licensing agreements), but BDB, TLOT, DBL Hebrew and TWOT are all available. In a pinch, these lexicons are more than enough to get me started.
Hopes for the Future:
Logos promises that in the future there will be a synching feature between the work you maintain on your home computer and the work you do on your iPhone. What this upcoming feature means is that if you write a text critical note on a passage that you are working on at your home computer, then that note will be available for future reading on your iPhone. This will greatly, in my opinion, enhance the overall value of this app.
I still have not been entirely enamored with Hebrew morphological searches on Logos 4, at the moment there are a few bugs that need to be worked out. However, I have been assured that these fixes are coming in the near future as well.
All in All:
This is an amazing app. that packs a huge punch by allowing you to take your theological library anywhere you and your iPhone can go. What is even more impressive is that Logos has decided not to charge you additionally for this service. I would highly recommend that iPhone users give this app a try. Now if Logos would only pick up the cost of buying a new iPhone, or at the very least a new mug. How about it guys, what do you think?