If you are working on a PC, I would recommend Legacy Family Tree available at https://legacy.familytreewebinars.com/index.php .  
If you are working on a Mac, you have two options: run Reunion available at https://www.leisterpro.com  or run Legacy using Parallels to run this program written for the PC.  If you go to the Legacy website, they have information on how to do the later.

Considerations:

• Whatever program or website you choose, start by entering a small tree to see how you like it.  Several of the software packages as a free version that you can try.  Until you pay for the full version, there may be limits on the number of people you can enter and the reports you can print out.
• All genealogy programs have places to enter names, dates, events and sources.  That said, each program has a different user interface.  It is a matter of personal preference as to which you prefer.
• One thing I particularly like about Legacy, is the way they deal with addresses.  If you entering information from a census they have a natural way to enter addresses (house #, street, town, state...).  Whereas in Reunion, for example, when you enter Census information you have two fields: Location and Memo.  You can enter the full address into the location field, but then you end up with many, many locations, and it is hard to sort them by state or for a mapping program to locate them.  If you enter only the town, county, state in location and use the memo field for the house number and street, then you end up with a more manageable list of locations, and can locate events that happen in the same place more easily.  However, the way this information prints out in reports is awkward. 
• I would look carefully at what charts and reports they can create as that is one place where they differ.
• Personally, I did not find the ability to link automatically to Ancestry useful.  The way Ancestry formats source references is AWFUL.  Not only is every other word Ancestry, but they leave out some information that I consider important.  Their branding is so over done that they claim they are the author of such documents as the US Census.  It will take you less time to do the transfer by hand than to clean up their mess.  Also, a manual transfer encourages you to really look at the information to make sure it is applicable to your tree
• Look at their customer support.  Legacy has the advantage that they have an extensive library of videos both on how to use their software and on general topics of interest to genealogists.
• On line v. on your computer:
  • I personally fell I have more control over my information if it is on my computer than online.
  • On line involves an ongoing fee to maintain full access to your information.  On your computer, there is a one time cost to purchase the software.
  • Geni is a cooperative tree in which other people can edit the information you enter.
  • Ancestry has a very limited ability to create charts and reports. 
  • I have not had much experience with My Heritage.
• Backup, backup, backup.  This is a good idea whether you are talking genealogy or just in general.  Whether your tree is online or on your computer, you should always back it up.  For example, if you tree is online at  Ancestry, you should periodically download a gedcom.  If your tree is on your computer, you should periodically save a backup copy (just in case you make changes that you need to later undo) AND you should have a backup off site, in case you computer is. damaged, lost or stolen.  Options for off site backup may be as simple as putting it on a thumb drive and giving it to someone else to keep. Another option, is there are a few commercial products you can purchase that will automatically backup your entire computer.

mab@...