I have fond memories of Killing Time, although many of them are the utter disbelief that what I was reading was allowed to be published, and reading excerpts to Trekkies for laughs. When I got Voyages of Imagination it was the first novel I looked up. Slash aside, the story itself is vaguely similar to the 2009 Star Trek movie.
I like the sound of your method, much more easy going. I'm just happy that I've come across so many really quality copies of these books, in great condition. And then ponder the realities of how many years old some of these paperbacks might be. Some of them don't look like they've been read, or they were read by someone who was really careful about keeping it in good condition. Killing Time is a casual curiosity to me. I wanted to have the uncensored version, but I'm not hung up on the slash content if it's good for a laugh. I also like and am fascinated with alternate timelines and realities, which is the main reason I will read it.
There was a really good used book store I used to go to near one of the places I used to travel to work to. I used to go there once a month and would make sure to stop at that store. That's where I got a lot of the books I was missing (the ones when I was in college in the 90's and the ones that were released before I became a Trekkie in the mid 80's). I found a lot of the old Bantam Star Trek books there that were in pretty good condition, and surprisingly a lot of those were actually first editions. I found a 1st printing of the very first Blish adaptation there from the 60's and I actually found a very good copy of a 1st printing of the Star Trek Lives! reference book there (I don't think the store realized what they had with some of those or they'd probably charged a bit more). I picked up a lot of the James Blish adaptations there (though I believe I still need one or two more) and I picked up a couple of the Alan Dean Foster Logs there. I even picked up an early edition of Spock Must Die with the original cover (I can't remember off hand if it's a first edition, but it's one of the first few at the very least). What's sort of amusing about those is I actually paid more for them used then when they were brand new. The list price for some of those old books was $1.50 and most used stores that I've seen them in has them for between $2 and $4. At an antique store I also found a first edition of Mission To Horatious from the 60's. I'm not sure how much it's worth, but considering it was a first edition of the very first original Star Trek novel and it was on sale for only a few dollars I most definitely picked it up. That one was in really good shape. But yeah, when I picked up Killing Time it was just purely by accident I got an original release.
Traditional. I don't believe it's available as an E-book (I'm not sure that any of the Bantam books are available as E-books)
It has been forever since I read "Vulcan!" (probably at least 15 years), but I remember liking it well enough. It definitely has some problems (the Spock characterization pointed out by Christopher being one of them), but I was somewhat fascinated by overall story idea and some of the technology described in the book (like the Psychiatry Tanks or whatever they were called). I'm sure if I read it now it wouldn't be as good. I know a lot of people really dig on "Death's Angel" because of the extreme Mary Sue character and all the wacky and ridiculous aliens. But, it is my favorite of the Bantam novels. I'm sure a lot of that has to do with the fond memories I have of the very first time I read it (back in the mid-80s when I was 12 or so) when I read it in one sitting on a very cold, snowy afternoon/evening when I simply laid around in bed under heavy covers trying to keep warm as I listened to the nearby (and somewhat ineffective) radiator pinging away. My mother brought me a cup of hot chocolate every once in a while as well. That fond memory probably colored my recollection of the book, but I've read it several times since then (most recently about five years ago) and I still find myself smiling in enjoyment reading it.
Sigmund was what they called the machine (I only remember because I just finished it). An interesting piece of technology. I always find some of the older novels interesting for what they bring to the table. They had to make up a lot of the continuity and technology themselves, since there was much less to work from.