When comparing Clementine vs Lollypop, the Slant community recommends Clementine for most people. In the question“What are the best audio players for Linux?” Clementine is ranked 6th while Lollypop is ranked 12th. The most important reason people chose Clementine is:
Clementine features competent tag managing for all music files, be it album art or just simple text entries.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Tag editing
Clementine features competent tag managing for all music files, be it album art or just simple text entries.
Pro Intuitive and fast to set up
Clementine is easy to get up and running with lyrics, equalizer, online info, etc., within minutes after installation.
Pro Sensible UI
A fork of the 1.X line of Amarok, Clementine favours usability over design trends.
Pro Very good folder organization
Organizes your music folder based on the tags of your library.
Pro Remote app for Android
There is a very good remote app for Android. The app lets you do a lot: from the usual volume controls to checking the lyrics on your phone. You can even download the songs from Clementine onto your phone.
Pro Supports a lot of online services
Clementine includes support for services such as Ampache, Google Play Music, Spotify, and many internet radio stations such as Jamendo and Icecast. It's also possible to search all available sources (local and online) at once, as well as mixed content playlists.
Pro Built-in equalizer for custom sound
There is a built-in equalizer with many presets from genre-specific rock, pop, and party, to experiences such as large hall and live. You can also tweak it yourself and name your own preset.
Pro Creates playlists based on past music you listened to
Clementine gathers the user's listening data to use for smart playlists. Clementine uses your listening history to play music similar to the music you play most - which typically is music you will like but maybe haven't discovered yet.
Pro Built-in format conversion
Users can format any of their music files to a different format with Clementine's built-in format conversion tool.
Pro Can display song lyrics
Fetches lyrics from several lyric providers.
Pro Looks good and is really responsive
Unlike some other players in this list, Clementine doesn't seem to go unresponsive in the Ubuntu 16.04 system and looks really good with options for Visualization too.
Pro Decent library management
Clementine allows the user to move and organize audio files easily. Some examples include the following:
- It's easy to find a specific album song (find artist, select album, select song).
- It's easy to add songs to a playlist and queue the songs.
- It's easy to rename files from their metadata (artist, album, song number, etc).
- It's easy to add cover images.
- There are options to find duplicates, untagged songs, etc.
Pro Super intuitive way of organizing and browsing albums and artists
You can view all the albums you have in one long list. Clicking on one of them will bring a popup at the bottom of the screen where you will see a list of all the songs on that album.
Pro Works fast and reliably
Pro Super flexible layout
The latest version has a good full-screen layout and is very responsive. Goes very smoothly from full screen to minimal player (also being a GTK+ app).
Pro Integrates with the MPRIS sound menu
This applies for most players in the "Linux world", but not for all. Therefore I consider it worth mentioning.
Pro Huge development
There is constant improvements, librem and gnome3 is possibly the future.

Pro Cloud music
Lollypop allow you to play music from the web (iTunes charts and search from Spotify).
Pro Integrates well with many desktop environments
One example being the conditional use of client side decorations (a.k.a. header bars) depending on the currently active desktop environment.
Pro Good party mode
Pro Clean, light and works very well.
The only one that can play a lot of files without to stop.
Pro Queue option lets you change what's playing on the fly
You can add songs to a queue, and then re-order or remove songs as you please. It works similarly to a temporary playlist.
Pro Online radio integration
The newest version features a nice interface for adding, browsing, and playing online radio stations. This gives you access to more music than you would normally have, which can help expand your music library for free.
Cons
Con Slow development
Very little development work has been going on for a while as of mid-2017. Nobody is responding to bug reports.
Con Bit perfect output no longer configurable
Audiophiles want to play their expensive HD albums.
Con Too bloated by default with things like LastFM that can't be removed
When you install it, you get ton of internet radios and services plugins, that you can't remove, only turn off. There is also useless stuff like artist info that doesn't work and stuff.
Con Not customizable
It doesn't allow you to modify its interface by dragging toolbars around etc.
Con Horrible user interface and confusing layout
Con Resource exhaustive
Clementine uses up to two orders of magnitude more CPU than VLC and takes up about 180 MB of memory, plus additional memory for spawned processes (tag-readers), while VLC uses 80 MB with no other processes.
Con Ugly
Con Goes crazy with CPU and RAM
Takes its toll on your system's CPU and RAM.
Con Default settings aren't great
Although this is subjective, you might have to do some tweaking before you like it.
Con Ugly ressource hog with no features and buggy without hotfix
And yet Nr. 1 recommended because of nerds being accustomed.
Con Slow to start in Gnome/Cinnamon
It takes about the same time to start as an IDE or Photoshop.
Con Doesn't allow gapless playback
Con Not a lot of documentation
Clementine does not offer a lot of documentation, which can make discovering its features a bit difficult.
Con Buggy
Clementine is probably the most fully featured music player for Linux, however it has its own issues. It crashes and experiences occasional memory leaks that can slow down your system.
Con Database regularly messes up
Con Sometimes messes up taskbar
Con Last.fm support is broken
Con Cannot choose which tag profile to use
I use Tag2 (ID3:2.4) which doesn't seem to be the default tag used and I can't see a way to choose this.
Con No way to search on filename
Con GTK App
Its a GTK app so integration in other desktops is terrible it also uses GNOMEs ClientSideDecorations so it will break many window managers.
Con No equalizer
Lollypop still does not have an equalizer.
Con Good party mode
Con No In-App Volume Control (0.9.242)
It has no in-app volume control, it has to be managed through system 'Sound control/Applications'

Con Requires a well organized music collection
Lollypop will be a pain to use if music is badly tagged. The setup is a one time thing, but it can be a pain to organize a large library.
