Any good alternative to Microsoft Office?

I use "open office "(mainly because it's free)

Open office is free, Google docs isn't terrible. You can maybe get Office 365 free with an edu email, I caved in this year and got office 2019 off Gamivo for $45.

Libre Office is the most compatible thing. If it's slow, you'll only have problems with other programs and you need to look at your PC for the issue.

Libre Office is much batter than Office 2010, used both for a long time

http://www.openoffice.org/

If LibreOffice is slow, try going to Tools->Options, then under "LibreOffice->View", try toggling "Use hardware acceleration" and restart. If that doesn't help, do it one more time.
Every so often (mainly after I update, strangely) it starts to lag on me and I've found that this helps. At the end of the process, I have hardware acceleration enabled.

I hate OpenOffice, but it's probably the closet to MSOffice.
LibreOffice is purportedly good, but as you've experienced - the dreaded laaaaaaaaag.

It shouldn't be, so there's a problem on your side with Libre, that's the one I was gonna suggest. That or Open Office but I hear Libre is better.

So I just downloaded free office 2018. https://www.freeoffice.com/en/freeoffice

Seems great so far. It's fast and snappy. And the best of all, it's got almost identical interface to MS 2007 at least as far as excel is concerned.

Downside is they need your email to mail you a CD key.

What are your system specs? I use Libre Office on my gaming PC and it's fine, but it should since it is a beast of a machine. I have an old notebook from 2008 that has a 2GHz Core 2 Duo CPU with 4GB of RAM, and Libre Office runs great on it.

"OnlyOffice Desktop editors" is the best alternative I know of!

It's almost like Office but free, cross-platform, lightweight and with only the essentials (Word, Excel and PowerPoint). Also unlike OpenOffice and Libre Office, it actually has a decent ui!

https://www.onlyoffice.com/en/download-desktop.aspx

I have Office 2007 on a CD-ROM, so every time I get a new PC I just install from the disc.

Sounds like you found a new option, so I hope it works out!

Look to be brutally honest it depends on what you are using it for, if you are doing light word processing then pretty much anything will do (does wordpad still come free with windows), I personally use softmaker office, which has a free variant https://www.freeoffice.com/en/freeoffice which you mentioned in a post further up the page, i have found it to be snappy on older hardware although my use is pretty basic these days.

I'm using Google Docs / Sheet / Presentation, it is enough for basic use
Or you can also use the Free Office online version office.live.com

it depends on what you need office for.

In a pinch, both OpenOffice and Google Docs will do fine. They're more than sufficient for the 99.9% of people who aren't even aware of half the things Word can do, and for the people who only use simple tables in Excel.

But if you're a hardcore professional power-user, there's really no alternative. The kind of programmed templates I create in Word just can't be done elsewhere, and when it comes to advanced financial models, Excel is so far ahead of the competition, that there is no competition.

For the most basic of needs, you have free M$ office online. I mean, if everything else doesn't do it for you.

I'm curious, why don't you just buy one-time purchase Microsoft Office and be happy forever?

I've switched to Libre Office for a very long time now. I've never had any of those performance issues mentioned here. It runs like a charm does everything you'd expect from a good office suite and more. There's even some really powerful features you likely won't find with many other office programs, like directly editing pdf files. Unlike MS Office it also runs on Linux and is free.

EDIT: There's also a small company in Nuremberg/Germany that has a pretty pretty decent office suite (well it used to be decent, it's definitely more than a decade that I tried their product. As I said, I'm pretty happy with LibreOffice). You could just give it a go with the free trial version? (see https://www.softmaker.com/en/ ).

If you need compatibility with MS Office, be aware that - unless that changed since I last checked - at least OpenOffice is still not fully compatible to OOXML files (docx, xlsx...). So, consider that if you need to exchange documents with other people that use MS Office. Not sure if it's the same with the other alternatives like LibreOffice.

Libre office. It's like open office, it's free, but better and more often release updates. So try it.

a nice solution if you have to use ms word and ms excel is ms office 2010 primer, which was free with some add inside.
its official download page is long gone, but if you look for it hard enough you can still find the installer floating around, together with the patch to make it compatible with win10.
it looks similar to office 2007 and still gets updates.

OpenOffice

Funny, the only thing I do not like in MS Office 365 is the ribbon UI system. I prefer the classic and time-tested version that is still there in LibreOffice.

If LibreOffice is slow for you, then it is a hardware acceleration issue. That one is rather common. If you continuously get it, you may try OpenOffice; although that one is more like a legacy version of LibreOffice.

FreeOffice only has the MS Office type ribbon menus, but that is it. It is incredibly limited and only suitable for the most basic home use. However, if your needs are that small, you might as well use the free web version of MS Office that comes with OneDrive or Google Docs. (Although in my personal opinion, Google Docs has the worst user interface out of the entire bunch, it is as if they deliberately put everything in places that never line up with how other office suite UIs work.)

If you want something with the new MS Office layout and not just the bare basics, I would instead suggest WPS Office. Assuming you are okay with its limited language support.

(Although, to be honest, you can find actually working keys for MS Office 2019, especially the simpler editions, for a few bucks on eBay from resellers.)