Occasionally there were conflicts or problems caused by plugins, and then I just troubleshot those and uninstalled or disabled plugins until I found the culprit. No big deal.
Whenever I use another computer that just has vanilla vim installed, without my own .vimrc on hand, I just touch ~/.vimrc and away I go. I just try not to spend too much time on such systems before loading up my own .vimrc. Again, not a big deal.
I really don't get people who deliberately cripple themselves by using fewer plugins or features than were maximally useful.
On the other hand, I was never a big fan of giant plugins that make a lot of choices for you. I like to make my own choices as much as possible, and know why and how these choices are made. So the plugins I install tend to be very specific plugins that are good at one particular thing that I feel vanilla vim is lacking.
At one point in the past, I did have a bunch of plugins (nerdtree, fugitive, surround, nerdcommenter, etc, etc) but they weren't that great (I guess because vim's scripting facilities and UI isn't optimal for writing complex IDE-like features) and were always conflicting or otherwise a hassle.
These days I get by with vanilla vim with a conservative vimrc and I don't consider my productivity crippled. The only plugins I miss are surround.vim and a commenting plugin.
If you like to try any plugins, sure go ahead but I don't think it's a good idea for someone new to vim.
When I install my own .vimrc on another computer, I just copy my whole ~/.vim directory over with it, and that's really all it takes to migrate. Easy.
As for plugin conflicts, I've found them to be pretty rare, and when they happen they've been easy enough to troubleshoot and then I just disable the incompatible plugin, if I can't find some other fix. The occasional incompatible plugin is no reason to avoid plugins as a whole.
Incidentally, surround.vim and commentary.vim are also why I wouldn't want to live without plugins. Everything else is expendable.
I always prefer using tags files to do code navigation instead of browsing files. With `:set wildmenu` (enabled in sensible.vim), using `:tabnew :edit :split` etc from command mode is also quite nice. For browsing, the default netrw is decent or I use ranger in another window.
What I could really use is a fuzzy finding plugin, I've heard Ctrl-P is nice but I haven't tried it.
Some of the worst D'oh moments I've had came from before I added tab completion to my .vimrc, because it almost completely eliminated errors that my typos introduced.
I also suspect autocomplete to be the leading cause of a particular set of subtle bugs - ones where the words on the page seem right but the function chosen has a surprising and uncatered for side affect.
When you reinforce to people that it is OK to code blindly ahead, grasping for the right calls at the last second you will end up with poorer quality code (although, it may be typed faster).
I am a believer in using as descriptive identifiers as possible to make the semantics of your code as clear as possible. If this gives rise to 5-word+ identifiers, so be it, providing it is done tastefully (and not for verbosity's sake).
As typing 10+ characters per function call/variable call can get tiring, lack of autocomplete can leads incentivizes the use of shorter names which runs counter to this philosophy, and leads to code being harder to read. (IMHO)
Or did you mean use Vim bindings in IntelliJ?
This isn't always enough for folks, who fall back to YCM or others.