Sileo real Cydia alternative has been released, and you can grab Sileo preview from default Electra repo now. It s a multi-contribution project made by experienced developers.
Device Compatibility :

iPhone XS, iPhone XS Max, iPhone XR, iPhone X, iPhone 8/8 Plus, iPhone 7/7 Plus, iPhone SE, iPhone 6S/6S Plus, iPhone 6/6 Plus, iPhone 5S, iPad 5(2017), iPad Pro 12.9 (1st & 2nd generation),iPad Pro 9.7, iPad Pro, iPad Air 2, iPad Air,iPad Mini 4, iPad Mini 3, iPad Mini 2, iPod Touch 6
Sileo Features
Old packages and setup will stay when switching to Sileo
Sileo will compatible with every Cydia packages and repos.
Cydia purchases can be accessible from Sileo.
Sileo not compatible with 32-bit devices.
Sileo not compatible with older versions such as iOS 10.X.
Here are some important news about Sileo
Sileo Developers confirmed Dynastic Repo supports with Sileo.
Sileo Developers confirmed Dynastic Repo successfully works with Sileo Package manager. Some few awesome apps are able to install with Dynastic Repo. ShortLook, TranslucentMessages, Countdown, TranslucentWallet apps are few of them. AppleBetas (@AppleBetasDev) is the main developer and designer of the Dynastic Repo. nullpixel (@nullriver) and Eric Rabil (@ericrabil) are the developer of this repo.
Sileo Developers
Sileo built by Atom Development. Here are developers who contribute to the Sileo project.
Coolstar :

Coolstar is American windows/ iOS and jailbreak developer. He is the developer of Electra Jailbreak for iOS 11.4.1 to iOS 11 versions. ClassicSwitcher 3, 3D Switcher, Anemone, ClassicLockScreen and ClassicLockScreen are the iOS projects done by him.
Alessandro Chiarlitti :

Alessandro Chiarlitti /@aesign is  italian UI designer and Coder. Electra toolkit designed by Alessandro Chiarlitti.
Coolstar tweeted a screenshot of Sileo on iOS 12 and Anemone.
According to the screenshot, seeing Anemone, he could be running a jailbreak on the iPad. Probably he is just testing the IPA. It might come with Sileo since Coolstar said it would be released soon.
Chiarlitti says Sileo is almost ready, Our developers just need to sort out a few things. Most probably it will release before the end of 2018.
Sileo coming soon according to developer recent tweet.
Entry of Sileo
There is no Cydia update from saurik for a long time. It is a long overdue Cydia update for iOS 11 onwards. Now it has arrived iOS 12.2 as the latest version & iOS 12.3 beta for upcoming version.  It seems saurik no longer being maintained Cydia. Also, recently Saurik has announced that Cydia Store has been shut down.

Therefore Electra team has planned to release a user-friendly alternative package manager called as Sileo.  Jailbroken users can download new jailbreak tweaks, themes, and much more through Sileo. It is designed  for 64 bit command line tools + libraries.

However, this is compatible iOS 11 onwards and not compatible with a backward version such as iOS 10. 

Coolstar published a Youtube demonstration video about how is the Sileo user interface in action.
Currently Sileo payment support only for the @DynasticRepo . It will be upgraded soon.
Version Compatibility : 

iOS 11.4.1, iOS 11.4, iOS 11.3.1, iOS 11.3, iOS 11.2.6, iOS 11.2.5, iOS 11.2.2, iOS 11.2.1, iOS 11.2, iOS 11.1.2, iOS 11.1.1, iOS 11.1, iOS 11.0.3, iOS 11.0.2, iOS 11.0.1, iOS 11

Download and Install Sileo

Step 01 - First you have to Jailbreak your device using Electra tool.

Step 02 - Then Launch Cydia from your iPhone or iPad.

Step 03 - Go to the Sources--> Electra’s iOS utility --> All pacakege --> Sileo (Beta)---> Install.

Step 04  - Finally, it will Restart SpringBoard, and you can find Sileo on your device homescreen.
Some important information about Sileo

* This is a beta preview. Some functionality is not finalised and bugs are to be expected.

* For now, the preview only supports the latest version of Electra.

* The source code will be published at a later date.
Nullpixel :

Nullpixel / @nullriver is a famous iOS Developer & iOS security researcher. He is the WWDC17 Scholarship Winner.


Apple Beta / @AppleBetasDev is a iOS and Tweak developer. Ultrasound app - Dynastic repo developed by him.

Kabir Oberai :

Kabir Obera / i@kabiroberai is an Indian iOS developer and WWDC 2017 scholar.  He is the Creator of Theos Jailed and upcoming Supercharge App.