PlusNet don't go out of their way to tell you what the speed of the uplink is. However, all the PlusNet triallists so far seem to report uplink speeds of 10 Mbit/s. But, as no-one can see the actual sync speeds, you have to infer this from reports of speed-tester results - where upload speeds are generally around 8Mbps (and downstream in the mid-30s).
So, so long as you make use of that uplink speed, then I think its a reasonable price.
As for the contract terms... Bob Pullen
reported here that they aren't imposing any annual contracts as yet. Whether this stays in place once the real packages arrive is anyone's guess...