If you’re just looking to replace RB951Ui with a newer device, then hEX refresh will very likely do the job nicely. If not for other things due to RB951Ui having only 100Mbps ports.
If you’re looking for a device with increased capacity (for potential future connectivity upgrades), then you should really consider requirements and only later decide on particular device model. hEX refresh seems to be on the lower end of current MT portfolio (regarding performance) with a few gotchas regarding ether1.