Apollo is a recently released project management tool, designed to take you where Basecamp has never been before. The interface and functionality of Basecamp never won me over so I gave Apollo a try.
There is a 30-day free trial -- long enough to see if it is something you take to or let sit on your desktop until day 29. Basic is $23 a month with a generous 18 projects, 5GB storage, unlimited project users, 7 CRM users, 5000 contacts, time tracking and 12 deals.
This is going to appeal right away to the niche that doesn't want to pay $49 for the smallest Basecamp monthly plan. The $48 Apollo plan gives you the same leg room as the Basecamp plan.
I found the user interface immediately friendlier. Overdue items take center stage, navigation is on the left and the lower left has the timers, which I found super-helpful for tracking project time right within my project itself. Another nice feature is the ease with which you can track those tasks that don't belong to any project but fritter away your day. They go under "personal tasks". You can even relate a task to a contact, for those time-draining clients or distractions.
The calendars are one of the highlights of this system, easy to use as a Google Calendar but Apollo does the work of integrating the calendar and your projects. With bright colors it makes it easy to see upcoming perfect storms of work and keep them under control.
If you get the impression I enjoyed using this tool, it is correct. There are the features that are not unique, but not missing, such as messaging with attachments, task lists, milestones, assignments. Nice touch is that files from message attachments and files from elsewhere end up all in the project folder.
There is even a feature to import your Basecamp files and Highrise contacts, and the ability to export your data. Clearly aimed at being a nice alternative if Basecamp hasn't been a good fit for you.
I also like DeskAway and PBWorks but my partners and clients had a hard time learning them and abandoned ship eventually. Apollo offers the friendliest user interface.