Thats a decision you need to make and not others for you. You can often call the carrier you are with and see what they offer you once u tell them you want to leave and go with someone else. Remember all carriers are the same as for their service and support.
In the end this is a decision you need to make on your own.
I've been on and off Rogers postpaid.
I can't speak for Telus since I've never been with them (I've only been with Fido, Bell, Videotron, and Rogers) and I can say that Rogers is better than Bell and Videotron. However, this doesn't mean that they are great/good/excellent since I wasn't overly impressed with my service from both Bell and Videotron. I left Rogers postpaid a few years ago because they would no longer match (or even better) what a competitor offered me. My phone was paid off so without any any reservations, I just ported over. The issue that I had with Rogers postpaid is because you prepay a month of service in advance (this is the same with almost all types of transactions from leases, to phone/utility bills, etc.) and you pay the "overage" for the previous month at the new billing date, it took them ~3-4 months to get my money back for my payment. Their typical excuses were we have to wait for the following billing cycle (by that time, it was already 2 months since I cancelled) to see if there were roaming charges since their roaming partners sometimes take ~1-2 months to submit the usage. I told them that my entire usage was in Canada since if they look at my usage report, they will see that calls & data were all done each and every day in Canada (no dates were skipped). They told me that I could have made a short trip to the US to use data or make calls/SMS. After ~3 to 4 months from the date that I cancelled/ported and contacting them back on a weekly basis, I finally got them to refund my money.
I didn't comment on Fido since Fido and Rogers use the exact same network (Rogers owns Fido for ~15 years or so). I've had Fido service before and after Rogers purchased them. With Fido, you won't get the higher end selection of phones if you always want to get your phone via subsidy/contract. Network is exactly the same. Price plans on Fido are generally better than Rogers.
I'm back with Rogers postpaid temporarily for one of my services because of they changed their maximum balance for Rogers prepaid. My prepaid balance was high enough that it would be next to impossible (unless I opted for services or made calls that I normally wouldn't do) to bring my balance down to their maximum of $150. The only option presented to me was to get a postpaid plan. After I exhaust my balance on their postpaid plan, I'll port my number out of their postpaid plan and into a different company's prepaid plan since Rogers doesn't offer great prepaid service.
In terms of whether you should accept Rogers or stay with Telus, it is your choice BUT if Rogers matches or beats Telus' plan and you have friends/family/co-workers on Rogers and they don't have any reception issues with Rogers (in places that you normally frequent), you should probably switch to Rogers. Where I live, Bell/Telus has better reception than Rogers especially in buildings. Videotron also offers better reception where I normally frequent but they are only available in the province of Quebec. This isn't to say Rogers is unusable in the places that I frequent (otherwise I would not be with them) but it is to say that when I go into elevators or underground, I will notice that my friends can continue their conversations on their cellphone whereas on Rogers I lose data and the phone cuts in/out sometimes even disconnecting.
Good Luck and keep your wits about you !
One other suggestion that has served me well is document every interaction you have .
As far as service and support being the same for all carriers ...I'm not buying that for an instant but I do agree that whether you like it here all depends on each individuals experiences here and you won't know whether it is the right thing for you until you have experienced it yourself .