Hi Amir,
Thanks for checking out our plugins!
With Event Tickets, you do have the option to require users to login before being able to RSVP (note that your WordPress settings under Settings > General > Membership will come into play here). They will also be able to see a list of their RSVPs when they are logged in (take a look at this article for more info and some screenshots). With Event Tickets Plus, you can collect additional information on attendees when they buy tickets/RSVP.
Regarding Ultimate Member, I’m not very familiar with the plugin, but enabling our settings to require users to be logged in to RSVP will show a link under the RSVP area that says “Login to RSVP”, which will take the user to the default WordPress registration form. If you want it to instead take the user to an Ultimate Member form, that may require some customizations to make that happen. If you’d like to give it a shot, I would recommend taking a look at our themer’s guide, which has some great info to get you started.
The good news is Event Tickets is free, so you can always download it and try it out!
Does that answer your question? Please let me know if there is anything else I can help you with!